It would avoid a lot of the poop storm EA is facing with this. It's presumably costing them millions, and it's something they could have predicted when the beta crapped out.
* Matchmaking
* Authentication
* Stats
* Chat
Things have come a long way since Battle.NET, you're really not going to find that backend servers for any modern game are a simple thing.
Hell, any game that makes use of GFWL is going to be heavily dependent on the GFWL SDK. You can't release that, as it's under a fairly strick NDA. The same with any SteamWorks game.
It's always easier spec'ing the amount of time something takes when you have no idea what goes into doing it and its not your job anyway.
Then it shouldn't take you more than a week to emulate it from scratch, right?