What kind of breeding did the pup come out of? Proven hunters that you saw hunt well or dogs with hunt titles behind them?
Weims aren't a consistent breed anymore as far as chance of finding a good hunter out of most any breeding. Not my opinion--that's what weim folks tell me.
But you said a few things that made me wonder if this dog isn't just fine. It might be a bit timid around other dogs, I'd work it by itself with a ton of encouragement and go easy on any commands. When it comes to training be firm and consistent. I would suggest if you go to a pro or with a training group that you find someone who knows weims and how they can develop differently than some other breeds.