The 2011 swap with Houston is only top 1 protected, and it doesn't look like that #1 pick is going to be a huge prize. You're looking at Harrison Barnes and Perry Jones as the best options to emerge as the #1 guy, and neither of them projects to be the franchise savior that you're looking for. Best case you're looking at a 25% chance of landing the #1 pick, and more likely a 5-10% shot. The Rockets are a solid bet to be around .500 again, so it's very likely that a 43-39 finish doesn't have a major impact on their draft position compared to 25-57.
Then if their 2012 pick is in the 6-10 range, they get zippo again and they have now tanked fruitlessly for 2 years and counting. Even if they land in the top 5 and get to keep the pick, they still need to get lucky enough to have the right guy on the board and savvy enough to snag him. And almost inevitably, they are going to land in the 6-14 range at some point from 2012-2015 and have to give up the pick.
Considering how long the team has sucked with Isiah fcking up and then Walsh cleaning up his mess in preparation for LeBron, it seems silly to continue the strategy with such a slim chance of building a championship caliber core through the draft.