What I found interesting is that one of the better pass rushers in the draft was still on the board when Houston picked in Illinois' Whitney Mercilus. Just look at this article from the National Football Post breaking down him and USC linebacker/end Nick Perry.
3-4 teams will like him because he has the athleticism to play on his feet and drop into coverage. In a way he reminds some of Jason Pierre-Paul from two years ago. Pierre-Paul was raw and only played 1 year of major college football, but he was the most instinctive pass rusher I had seen in years. Mercilus has some of those same traits.
The luxury good teams have is to take a player who won't necessarily start right away. Houston could grab a more raw prospect like Mercilus and put him in a rotation with Brooks Reed opposite Connor Barwin. That means Mercilus could grow up in the system, learn more about, you know, being a football player and blossom into a big-time star for Houston.
As the comparison above says, Mercilus could be on a path just like Jason Pierre-Paul. He could also end up like a ton of pass rushers who were raw and never worked out. If you remember, Mario Williams was also considered raw as a pass rusher before he was selected too.
Of the two guys listed in the article above, I'd rather the Texans go after Nick Perry, but Mercilus is an intriguing option.