Using FIFA 2004 / EURO 2004 as a base, here are my top ten suggestions:
1) PRE-GAME
Many varied pitch entrance scenes exist and are done well. Perhaps add some panoramic shots of the stadium (inside & out), and some fan close ups before we see the players. A team lineup display would be fantastic, particularly if the analyst takes the time to run through the players and formations, and if possible the teams' recent form.
2) GAME CINEMATICS
Some generic goal celebrations, some player specific, as already exists and is done well. Picking ball out of net when trailing is needed though. Yellow and red card cutscenes done well but need more variance. Dramatic moments like last minute goals and penalties should be reflected in that manner. Substitutions need cinematics. Manager cinematics would also be welcome, but perhaps unlikely with licensing concerns. TV style replays, multiple stat popups and time/score boxes to be replicated as close as possible.
3) POST-GAME
Cinematics already exist and are done well, but the man of the match should not be celebrating if he's on the losing team. More commentary should focus on the impact the result may have on future games (not in friendly mode). Choice of golden goal, silver goal, shootout, classic extra time or draw should be available like Euro 2004, and should be a default setting in the options for friendlies.
4) TITLE/TROPHY WINNING
The last couple of EA titles have been very poor in this regard. At least forty seconds of commentary and cinematic should be devoted to a title or trophy win, with maybe two or three variances (one for teams who were the favorites, one for the upset winners, etc). Accepting medals on podiums would be a nice bonus, but at the very least, a holding up of the trophy with celebration, and dramatic commentary to reflect the achievement.
5) GAMEPLAY
Too big a topic to cover, and others will do that for me, but game speed option is essential. Slow - Normal - Fast at least, a slider if possible. Make freestyle easier to perform, but only with the players of high skill. Euro 2004 is the best FIFA in recent memory, as through balls and intelligent running are essential. Off the ball was too difficult, stick with the Euro 2004 formula. Except add the freestyle defensive options and the ability to slow down & hold up from FIFA 2004. Goalkeepers should get cards too.
6) GRAPHICS
Done well, not much I can add. But weather is essential. Dynamic weather at that, effecting gameplay. Day & night options paired with weather options are an integral part of any football game. Perhaps default to the weather settings of the home country or stadium for that time of year (based on the console clock) in friendly mode, but with the ability to change it. Also very important is that the big teams are done right. Get the Champions League calibre sides sorted with real faces before worrying about the minor teams. Rotating and electronic adboards depending on the stadium, with one blanket advert at a time in some places (Stamford Bridge an example).
7) LEAGUES
Ten essential leagues - England, Spain, Italy, Germany, France, Holland, Portugal, Belgium, Turkey & Scotland. After that, localize the leagues in the game. PAL version contains other European leagues deemed important for marketing. An NTSC version for Japan and Korea has J-League and K-League. An NTSC version for North America has MLS and Mexico. An NTSC version for South America has Brazil and Argentina at minimum. World Cup and Champions League style competitions are essential, unlicensed versions expected due to licensing. Perhaps a Euro Super League similar to 2003 Club Championship. Plus custom tournaments with one or two leg, league or knockout options, with as much customization as possible.
8) LOCALIZATION
Commentary and menu languages unique for different versions. PAL has English, Spanish, French, Italian, German at least, maybe Portugese and Dutch (assuming they all fit on a console DVD). NTSC Far East has English, Japanese and Korean. NTSC North America has English (UK), English (US) and Spanish. NTSC South America has English, Spanish and Portugese. But please DON'T over localize - having five available commentaries on FIFA 2003 Xbox added greatly to its replayability. Leave the option there for international gamers. Don't just make an English only PAL version for the Pacific Rim as an example, like my Xbox version of FIFA 2004 (you monsters!).
9) STADIUMS
Somewhere in the range of 30 would be great. A recommended list - Highbury, Stamford Bridge, Old Trafford, Anfield, Bernabeu, Nou Camp, Riazor, Mestella, San Siro, Delle Alpi, Olimpico, Westfalenstadion*, Gottlieb Daimler Stadion, Arena auf Schalke, Stade Louis ll, Vélodrome, Stade De France, Amsterdam ArenA, Philips-Stadion, Dragão, Luz, Constant Vanden Stock, Atatürk Olympia, Celtic Park, Maracana, La Bombanera, Azteca, Yokohama International, Cairo International, Millennium Stadium (Cardiff). I would have suggested Munich's Olympic Stadium instead of Westfalen, but as I understand it there's some licensing issues there. Perhaps include the under construction Allianz Arena instead.
10) AUDIO
John Motson has been outstanding, but he's been the voice of FIFA for nearly a decade now, including four tournament specific games. Perhaps it's time for a change. The only other match caller in Motty's class is Martin Tyler. As for the analyst, Andy Gray is the most logical if Tyler/McCoist can't be done. The commentary needs to follow the action more closely, and isn't as near to TV style as it really should be. The chants are excellent (FIFA 2003 particularly), as are the in game sounds. I understand the issues surrounding EA Trax and Xbox custom soundtracks, so please at least continue to allow us to turn certain songs off (which you have done in Euro 2004, thank you).