I just don't like the fit with Clowney in the 3-4, because he's too slim / not strong enough to play DE in the 3-4 and very rarely, if at all, drop into coverage to play a 3-4 OLB. (Watt is 6' 5" 290lbs, and Clowney is 6' 6" 250lbs) I see Clowney as a taller Dwight Freeney, who was very quick off the edge(4.48: 40 yard dash in 2002.) Freeney moved from 4-3 to 3-4 and he dropped off the face of the Earth. Clowney is the purest form of a 4-3 DE, it's quite amazing.
Michael Vick is passed his prime as a starting QB, as he can't stay healthy, and when he is on the field, he turns the ball over a lot. While I like AJ coming out, giving up on him after one year after basically being a first round pick would just be beyond dumb, they wouldn't draft a QB the following year after getting AJ at the top of the 2nd.
While Manziel / Bridgewater aren't as an elite prospect as Clowney is, a QB is such an important piece, especially the Texans, where they have a bunch of talent, just not at the QB position. While I don't think any QB in this class is an elite of prospect that Stafford / Luck were coming out of college, they have a projection to be a Top 10 ~ Top 12 QB and combine that with what they have on that team, that could be deadly.
I think they should think about trading down a couple of picks and maybe pick up either of the Tackles or Mack / Barr to play OLB for them. Mack would be awesome for them, as he's an outstanding pass rusher.