Probably would've been United States champion, or feuding with The Miz in one way or another. Hell he could also simply have been a mid-carder who were doing some slightly insignificant feuds, or significant, I don't know. There's a lot of things Bryan Danielson could've been doing had he not gone to FCW. But I think it was a good thing really, to get him with the NXT crowd, and to get him known through that.
Main event? Absolutely not. Not yet, he still has a bit of a way to go, and would definitely need to establish himself a bit in the mid-card before they should even consider putting him near the main event.
Absolutely not as well. He's over, and he's known as a great wrestler. He has a lot of potential and all that, he would definitely be getting some kind of push, but it wouldn't be an immediate shot to the top.
Somewhere in the mid-card, or maybe United States champion. Really nowhere else if you ask me. There's not much more they could've done with Bryan prior to that, or could do with him now and make it seem legit.
Probably not. Sure he could've simply been postponing his debut until NXT, however I seriously doubt that considering he was offered a RAW roster spot. He would most likely have avoided NXT alongside FCW.