Pheace: As far as I know at least that's simply a conclusion that has been drawn. It's possible that the new agreement means they want the DLC to be offered on Steam as well. (which certainly would help prevent compatibility options). And yes, that means they want/get a cut.
You do realize that EA don't use SteamWorks for their games, and that exes differ just by a few lines of code that call for Steam on launch, so compatibility issues are off the mark here...
In fact, what EA's doing with this is improving compatibility, since you can get the game from whatever service you want, and you'll be getting the DLCs directly through the game, as simple updates for it (meaning the DLCs will have a consistent code no matter where you bought the game from).
TwilightBard: In this case, I'm not on either side, it's childish on both ends but EA really is the one that comes out worse for it. There are simply other ways of working around what they're doing, they just refused to do it.
Why should they want to work with Valve? Considering that EA is one of the biggest publishers, they can easily do whatever they want with their games without worrying whether they would sell or not.
