It depends on what they would net in return. But Clowney looks like he's going to be the real deal. He has a prototypical build for the NFL and a wide array of moves he uses to beat opposing LT's. Pairing him with Watt on the same line would be a nightmare for any of the QB's in that division.
As much as the Texans need a QB, they should take Clowney. They have a legitimate chance to have the greatest bookend defensive ends in the history of the NFL with Clowney and Watt on the same roster.
Looking at the starting QBs in the NFL to end 2013-14 there were only six that were #1 overall selections.
• Carson Palmer-2003 (1)
• Matt Ryan-2008 (3)
• Joe Flacco-2008 (18)
• Thad Lewis-2010 (undrafted)
• Cam Newton-2011 (1)
• Jay Cutler-2006 (11)
• Andy Dalton-2011 (35)
• Jason Campbell-2005 (25)
• Kyle Orton-2005 (106)
• Peyton Manning-1998 (1)
• Matthew Stafford-2009 (1)
• Aaron Rodgers-2005 (24)
• Matt Schaub-2004 (90)
• Andrew Luck-2012 (1)
• Chad Henne-2008 (57)
• Chase Daniel-2009 (undrafted)
• Ryan Tannehill-2012 (8)
• Matt Cassel-2005 (230)
• Tom Brady-2000 (199)
• Drew Brees-2001 (32)
• Eli Manning-2004 (1)
• Geno Smith-2013 (39)
• Terrelle Pryor-2011 (supplemental draft)
• Nick Foles-2012 (88)
• Ben Roethlisberger-2004 (11)
• Philip Rivers-2004 (4)
• Colin Kaepernick-2011 (36)
• Russell Wilson-2012 (75)
• Kellen Clemens-2006 (49)
• Mike Glennon-2013 (73)
• Ryan Fitzpatrick-2005 (250)
• Kirk Cousins-2012 (102)
The Texans can find a very good QB later in the draft or they can trade for a Mallett or Cousins who will likely be just as good as any of the top QBs in the 2014 draft class. There is no sure thing like Luck or Manning in this draft.