Texans are up there, but they cannot be No. 1 until they start forcing more TO's. They are middle in the pack in INT's and fumbles. Being great at getting the offense off the field and not letting them score helps a lot, and can be used to win a Superbowl. But in games like today's game, even just 1 forced turnover with good field position wins the game likely for the Texans. Great defenses do more than just stop the other offense. They create super short fields and great opportunities for their offense and energy the fans and team when they get turnovers. This is the next step, and to do that there still need to be improvements such as replacing Kareem Jackson with a CB with better ball skills.
As long as we line up Jason Allen/Kareem Jackson at CB2, we won't be a better defense than the 49ers.