The new EGM has a feature on this game and it sounds like what they're really striving for that can't be done in the current generation consoles is the 50+ player multiplayer they're going to have. There's a few other things they mention about enemy AI and such, but that was the big one.
The new EGM seemed much more conservative in its hype of XBox 360, more than I can remember them being with other consoles set for release. In fact, they came right out and said they were underwhelmed with most of what they saw for the new console. Wonder how much their opinion will change once they start seeing games closer to completion.
Got to keep in mind that these are running on Alpha development kits that only allows for 25% of what the system is capable of. Come July, we'll probably start seeing some incredible stuff on the Xbox 360. Developers are currently working on finalizing the hardcore programming of some of the launch games. Once the beta kits show up, that will improve framerates and graphics.