If you were an NFL GM or talent evaluator, and you were charged with selecting a franchise quarterback for your team, what would you rather see from a prospect? Willing to try to impress you with all of his talent (while potentially failing to do so), or play conservatively with the expectation of resting on his laurels?
I'd take the first guy, confident enough in his abilities to show them off. But that is why I don't work for an NFL team, and why I don't organize Mock Drafts. SB Nation just came out with their latest 2011 NFL Mock Draft and they have Blaine Gabbert (who elected not to throw at the combine) at first overall to the Panthers, and Cam Newton (who threw but failed to impress) at twelfth overall. Quite the difference.
As for the Texans, they have them taking Wisconsin DE J.J. Watt, here is their rationale.
Unless a cornerback is miraculously available here, expect the Texans to add a front seven defender - ideally a lineman - for Wade Phillips' 3-4 defense. Watt is quietly garnering Top 15 consideration as a five-technique end, and fits Houston's need perfectly.
Where Watt will play at the next level is kind of up in the air. He might not have the size to play DE in a 3-4 and certainly doesn't have the speed to play OLB. That can either be seen as lack of a natural position, or the benefit of versatility. Watt could probably play in a few different spots in the Houston defense, and could be a good addition to a team looking to implement a new defensive scheme.