I think that EA would do well to improve the customisation options available in the game. Not all of us want to play Serie A or the Premiership all of the time - bad local teams and fantasy squads are much more fun.
To this end, it would be helpful if...

1) We could have longer player & squad names.
2) All of the kits were fully customisable - not all the kits in F2K picked up all of the colours (a bug).
3) Customised players didn't pick up initials of previous goal scorer whenever they scored. How this bug passed the playtesters, I don't know.
4) Customised leagues didn't lose teams from the end of the final table. Again - another bug that slipped the net.
5) The cup & tournament generator had more options.
6) The in-game simulator generated a few more quirky results & responded to in-game tweaking. There's never any results of 5 or 6 nil generated and once the season is underway, no amount of changing squads or tactics makes the slightest difference. I know this isn't a management game but one would have thought squad strength and tactics counted for something.

It goes without saying that a bigger pitch and slower gameplay would transform the game.
And as for the "bicycle kick which fooled them all" - it would help if the players didn't all stand around dazed and immobile after someone failed to connect.