From a business standpoint it makes a lot of sense to make it multi-platform. The game has been in development for a long time and has certainly cost them a ton of money. For a long time there was the idea that the PS3 would be the super dominant console of this generation, but that obviously didn't pan out. Now there is a huge cost sunk into a project that might clearly won't be able to make the returns originally planned. At this point you have to start crunching numbers and seeing if you are getting the return on your investment you really need to make the project a success.
At this point multi-platform release starts looking very attractive. You can target more than 50% of the market and stand a good chance of seeing a great return. So SE goes and starts to strike a deal with Microsoft. Ahh but here there is trouble. Microsoft wants to utilize the game as a system seller and not just a last minute port. So they pressure SE into a simultaneous release with a combination of threats and sweet talk I imagine. SE promises a simultaneous release in the western markets because it will take them a while to localize it anyways so why not have the coders do some work. This all makes way more sense to me then Microsoft trying to buy a game from a series that is almost exclusively single platform.







