Just because you're favorite car doesn't come in a color you want, you don't buy it? If you're a fan of Battlefield, regardless of the developers or associated companies problems, buy it. It shouldn't really matter.
If you're worried about communication with friends, or stat comparison, I'm sure Origin has that. Not to mention you could add-non steam games as someone stated above (As long as it's supported). On top of that you have Raptr and Xfire you could use. VENT!
If you're worried about resources. If you're actually capable of running BF3 at decent settings, you should have a decent enough rig to not worry about a 20mb program. The Phenom X4/X6 and soon bulldozer CPU's as well as the i5/i7's should be able to multitask just fine.
If you're worried that because it's not on steam, you have to go out and buy a hard copy, EA has a download manager, which is not that hard to use, and I'm sure Origin has the same. I live in a small town that is 15 miles from a bigger town. My town doesn't have a store that would carry such things as even 360 games. Steam is very handy, but if I have to DL by other means, it's not that big of a deal.
Reading this thread makes me look back when CoD: MW2 came out. When everyone found out that they took away server support and console so everyone canceled their pre-order. Is everyone back at that level? Just because it's not on Steam?