Summary: Blatter wants to alter the away goal rule in the knockout stage, as he said its quite old. The away team in the 2nd round has a possible advantage of 30 min extra. That makes sense. And for the first time, I completely agree with him.

I think it would be best if the away goal starts to count after the 30 extra minutes in the 2nd round (if applicable)

Source:
FIFA president Sepp Blatter has called for a rethink on the away goals rule and questioned whether the method for settling knock-out games still makes sense.

The system - where the team who has scored the most goals away from home wins the tie if the scores are level - has been used since 1965 in European competition and still applies in the Champions League and Europa League.

'In reality it favours the club that play away from home in the second leg. Where the scores are tied, that team has 30 minutes more than their opponent to score a valuable away goal. After all, in the first leg there is no extra time.' said Blatter.

http://www.dailymail.co.uk/sport/football/article-2787160/FIFA-president-Sepp-Blatter-questions-fairness-away-goals-rule-knock-games.html

Agreed tuan, im not a fan of changing the rule anyway, the field importance may be underrated, ok about thefans support but the home team can use many details.
For example, if you want to favourise action in the game, you make the grass a little wet to favourise possession and short passing, or make the field harder to play ( intentioally or not ) against teams that need to pass the ball more often, this advantages more the long ball style and aerial playing style.
For Camp Nou, for example is made to suit the style of the team, very big pitch that makes rival run and favourise possesion, some play in the mountains like in South America while its very hard for rivals to breath....
Some small details that have their importances in high level specially in the final game of the second leg where its a deciding game.
For the algorythm, i cant see any better change and it may complicate the rule for the new Football fans and practicers.

@Tuanis,

"EXTRA TIME AFFECTS BOTH TEAMS EQUALLY"

That statement in an of itself is true only if nobody scores. The point is that in extra time, the home team has infinitesimal more to lose than is made up by them playing at home. Your assumption is hinging on the fact that being at home actually makes that much of a difference when in fact recent statistics have shown that the idea of a home advantage is slowly diminishing. On average in the PL, home teams win 40% of the time, Away teams win 30% of the time and they draw 30% of the time. Those stats are compelling enough to make you realize just how much the current system is favoring one side.

Furthermore, those stats are even more compelling when you take into account that they only apply to 90-minute games where teams still have sufficient energy to fully take advantage of crowd support.

@TheGame: thanks for the stats. Good stuffs. Just want to add that: playing at home when you were loosing in the 2nd game and going to extra time would actually back fired because of the pressure, especially when you are the "stronger" team

@tuan_jinn, exactly. And at that point you have no choice but to attack, potentially leaving you more exposed. And isn't that the whole argument? Is home advantage really that advantageous in those final 30 minutes? My answer is no. Obviously the stats I provided only apply to the English game, but I would really like to see some home advantage stats in the CL as well.

@TheGame

I still think that playing at home and closing the fixture at home benefits the home team. This new idea of the away goal rule will just give the home team even more chance to win a fixture. The one the plays the second leg at home are the ones that end first in their respective group so they would be "the better team". Having the away goal rule removed for et will favour the home team even more.

Also, if you believe that home advantage is not really a thing to take into consideration or is insignificant then the better option would be to remove completely the away goal rule.

You are using only english data to support your argument which is fine, but consider that english football is not the strongest atmosphere-wise and cant be compared to other leagues like Bundesliga in that matter.

I would prefer for that rule to disappear.
but... If the away goal rule applies for the first 90 min. then it should apply for the et as well. Why would it be fair during the first 90 minutes but not on the last 30? one team gets home advantage for 30 more minutes and the other team gets the away goal rule in their favour for the same time. If you say it should be removed for the last 30 minutes is because you think the away goal rule is a bigger of an advantage than playing at home.

The rule is created based on the believe that playing at home is a very big advantage and therefore it makes a difference in a fixture so to counter that "advantage" the rule awards the team playing away another kind of advantage in which if they score they would be granted an extra goal in case of a tie to in order to settle it. This as a reward for scoring in the away condition because it is harder to do so.

Im making assumptions here to explain why taking away this specific rule for et make absolutely and entirely no sense at all..

The Away Goals Rule In Extra Time Is Fair To Both Teams.

Omar presented some very informative stats on his blog concerning the progress of teams in the knockout phases of such competitions as the Champions League, where away goals allow the visiting side to progress either at the end of normal and extra time. The only way that such ties can reach extra time is by the first leg score being identically reversed in the second match. In these instances, the home side has an extra 30 minutes of home advantage in which to progress and to balance this advantage, the away side can claim the decisive away goal if the goals scored in extra time are equally shared between the teams.

Omar's figures hint at the apparent fairness of this bargain because the number of home and away teams progressing without the need for a penalty shootout is reasonably equal. This is what we would expect if the quality of the home sides in the second leg was equivalent to that of the visitors over the course of the sample.

A theoretically based approach to the problem involves modelling the outcome of an extra 30 minutes between two equally matched sides to see if their chances of progressing in the extra time period is roughly equal. 1.4 goals per 90 minutes would be a typical goal expectancy for the home side compared to 1.0 for the visitors. However, over a 30 minute period these values would be greatly reduced. Figures of 0.57 goals and 0.41 would be typical values for the goal expectations of each team over final 30 minutes of the 90 in such a match up. So if both teams played in a similar manner to a normal game, these are the kind of goal expectancies we would see in extra time.

At the end of 90 minutes of the second leg, each team will have had an equal amount of playing time on their own turf to have built up a winning advantage. Therefore it is desirable that the extra thirty minute format shouldn't unduly favour one side over and above the difference in ability between the sides. So for two equally matched sides, the chances of progressing should be as near to 50/50 as possible.

Once extra time is reached, the home side has two routes to winning the tie. They can take and maintain a lead in extra time or they can keep the game scoreless and then progress on penalties. The away side has the same opportunities to reach the next phase, but also can progress with a score draw in the additional 30 minutes of play.

Chances Of An Equally Matched Home Side Progressing From Extra Time in the UCL. ( per cent )

Team------Win in ET--------Draw ET period 0-0.----Win Shootout.---Overall Chance of Progressing.
Home Team----32-----------------38----------------------50--------------------------51

Chances Of An Equally Matched Away Side Progressing From Extra Time in the UCL. ( per cent )

Team.-------Win in ET--Draw ET period 0-0--Score Draw in ET--Win Shootout--Overall Chance of Progressing.
Away Team-----21--------------38------------------9--------------------50---------------------49

We can get a reasonable estimate of the chances of these individual outcomes occurring from a Poisson based calculation on the decayed pregame goal expectancy of our generic, equally talented home and away sides. For the shootout I've assumed each side has an equal chance of winning the penalty kick contest.

Either by accident or design, by allowing the away side the opportunity to still score an away goal in the additional 30 minute period, UEFA have almost entirely eliminated the home side's advantage of playing a larger proportion of the tie on home turf. The rules as they stand excellently perform the task of adding an extra half hour of potentially dramatic open play action, while still remaining fair to both sides.

From : http://thepowerofgoals.blogspot.fr/

@tiki_taka, that was an excellent read. I would like to know where the researcher pulled those proportions from, but if those values are empirical (I stress, NOT theoretical), then I would stand corrected and will agree with Tuanis.

@Tuanis, I am curious. if there was data present that would strongly suggest that the home advantage doesn't really exist, would you agree that we should remove the away goal ruling in extra time?

Blatter's words of wisdom.

@TheGame
Actually no, if there was that evidence then the rule should be removed completely, not just for et.
By removing it partially there would be one team who is favoured over the other, in this case the home team will be given a slight advantage. Do you get my point now? Im just trying to go in favor of the fairest rules were in a fixture both teams have equal chances of winning when it comes to rules. I would consider that removing the et away goal rule will make it even harder for the away team (weaker team) to win the fixture.

@Tuanis, lol so I said if there was evidence that home advantage DOES NOT exist would you concede that we should get rid of the away goal ruling in extra time. Then you replied well no, because the home team will be given a slight advantage. But I do get your point :) It seems like we'll be stuck in a limbo until we know whether away goals should be counted as high as they are and/or whether home advantage exists. With that being said, last season, surprisingly, out of all the games played, only the final went to ET and away goals decided one fixture (Chelsea-PSG), so I am surprised that this argument came up now because really it was rare to see away goals deciding a match last year.

I think the away goal system is silly. Part of that is because I'm an Arsenal fan and we keep getting done by it in the round of 16, but I think that the idea of an 'away goal' is dumb. Getting an away goal is not a task so difficult that it should decide the outcome of a two-legged tie.

Anyone changed their opinions now???

Found this (don't react to the sentence at the bottom, thanks)

I almost agree with what you guys are saying that having 30 extra minutes to score an awaygoal is not fair. Yes there is a home advantage but this is not a factor as big as it was 50 years ago and it is not as good as having 30 extra minutes to score an away goal..

But here's my point, There has been many statistics on how the team that starts away eliminate the other team in the end, 70% to 30% something, numbers calculated over many fixtures. so isn't the unfair 30 extra away goals minutes a bit of a counterbalance to the fact the team starting at home has statistically much higher chance of being eliminated?

i HATE the away goals rule

If we are to keep the away goals rule. We have two major options.

Away goals count as normal goals in ET.

Or, no ET.

I'd like to have no away goals at all. The debate then is about if we have ET or not.