Most teams that make deep playoff runs (and those that win the Super Bowl) usually have one or more players that go way beyond who they are on paper. Recent examples we could cite are Eli Manning and Justin Tuck.
Eli was a decent-to-good quarterback during most of the season. As the Giants approached the playoffs, Eli's play continued to improve. He was a great-to-elite QB during the run up to and including the Super Bowl.
The Patriots were probably equipped to handle the elite pass rush of Michael Strahan and Osi Umenyiora. What made the Giants' pass rush unstoppable was the great-to-elite play of Justin Tuck. He was largely unknown to anyone outside of Giants fans before the playoffs began, but Tuck becoming a great pass rusher tipped the scales in New York's favor.
The phenomenon isn't limited to last year's champs, either. A year before, the emergence of Joseph Addai and Bob Sanders as great-to-elite players made the Colts the Super Bowl champions.
The Texans have a solid nucleus of young stars. Guys like Andre Johnson, Mario Williams and DeMeco Ryans are all Pro Bowl caliber players.
Who else is there on the roster that, if they raised their game to the good, great or even elite range, would completely change the makeup of the team and move the Texans from a darkhorse playoff shot to a legitimate Super Bowl contender?