I'm not sure that hit JT took in the Miami game underscores your point exactly. That's not the usual kind of hit our QB's take in this offense and I think most QB's would have been shaken up after a hit like that.
I still think the concern about his durability is overblown. Yea he's a little on the small side. But I don't think it means he's going to break when someone touches him.
I definitely think most QBs would have been shaken up, but most QBs would probably been hit lower around the back and not high enough to get a concussion. Getting hit when your around 200 lbs is different when you're getting hit at 175 lbs. Not much cushion there to soften the blow.
I've said it in other threads, if JT learns to not take full on blows like Tevin did, I wouldn't be worried. We'll see...lots of time left between now and the first game. Those quotes from him in the AJC article certainly didn't ease my worries about his durability.