This isn't always the case, since ES'a NHL07 got better scores on 360 than current gen consoles. But, for the most part, these 360 games are getting low scores for a couple reasons:
1. In the case of EA, they have decided to completely re-do the engines for all their sports games, like Madden, NBA Live, NCAA Football, NHL. In that case, you're having 360 games with gameplay that is still relatively new and unpolished, going against current generation versions of the same game, which have been refined over several years. Not an excuse at all, but you can see why most launch sports are pretty graphics and nothing else. As 2K goes though, they have decided to just port their current gen versions over to 360, and just improve the graphics a tad.
2. Missing features. Some people say this is going on so that publishers can get you to buy 4 years worth of a sports game, so that by Year 4, it will finally have all the features that it's current year, current generation version has right now. Perhaps. But when you're building an entirely new game from the ground up, it's probably just easier (and safer) to focus on making the core gameplay as good as possible, then use whatever extra dev time you have left to add features. It comes down to this: would you rather have a completely new, fresh playing game, that is light on the options, but looks and feels next generation, or would you rather play the same basic game you've been playing for years, with slightly improved graphics (which aren't a significant improvement if you have a SDTV), and all the features you've come to expect?
Me, I'll just stick to current gen sports games, there hasn't been anything on 360 so far that's really impressed me.
