I think all of us would like to see tight ends that make pass catches. However, one thing that should be pointed out that the TEs in the Bills offense are called upon to block, and block quite a bit. Note, there has been better pass and run blocking in the resurgence of the past 4-5 weeks, and a huge part of that is the fact the TE are first blockers, pass-catchers second.
That being said, it would be nice to see them more involved in the offence. And like a few have already said, I agree that Nelson is more than capable, but he missed significant game, and even more significant, practice time. I do think he is the long-term answer, and Stupar is an adequate back-up; thus, in my opinion, there is no need to waste a draft pick on a tight end. The Bills have far more pressing needs.