He's definitely had issues in the few opportunities he's had, and maybe he is injury prone. I just wouldn't put concussion in that category.
As far as his inconsistent play goes, he's still only played not even the equivalent of 3 full games yet. I'm not saying he's the savior either, just saying not even 3 games does not a career make. He hasn't had enough time to get comfortable, get into any kind of rhythm. Granted, due to injuries, but still. He looked pretty decent one game, not so much the other, but certainly not enough time to pinpoint any flaws in his game. IMO anyway.
Yeah, we're in QB hell. No doubt about that. But that's what happens when you draft just 3 QBs in your 10 year run as a GM, and not one of them higher than the 4th round. There's where the problem lies.