I think you guys are missing the upside of all this: We'll finally be able to play as Garrus. Garrus! We'll be able to shoot sniper rifles and be badass and everything.
Honestly, it doesn't bother me. I prefer single-player, but sometimes co-op is fun. I'm not sure what the squadmates will do while Shepard is talking to someone, but that could be fixed by having co-op be a separate mode that doesn't contain the talky bits.