I don't see how defense is an issue. No opposing guards are getting easy buckets with Bledsoe and Allen. Dwight Howard is the best defensive anchor there is in the league and Pierce can still hold his own against any wings in the NBA. Harden and Lee are the only "weak" defenders I suppose, but with Howard next Lee, and Harden getting help from Bledsoe, Allen, and Pierce, I doubt that would even be an issue.
But putting Allen means benching either PP or Beard (I assume), that's a lot of offense to give up for defense.
Sure, that's a hard wall to break, but Tony Allen will not give this Rockets team any points.
As for Harden and Lee getting helped by Howard or Pierce or Bledsoe, well, maybe.
Bledsoe is a heck of a defender, but will he be able to effectively defend SG's at 6'1"? Those are Harden's covers that he blatantly ignores (especially those back cuts). That may be a tough out. Pierce may be a bit slow for SG's as well.
Watched a lot of David Lee games (all of it actually), he's actually a solid one on one defender. My concern is, if Dwight, say, get's stretched out on the pick and roll and leaves Lee down as a help defender, that's trouble. That's what he's bad at. He doest give effort on challenging shots, nor gives effort to even close out (on most occasions).
Dont get me wrong, I still think this Houston team is at worst, top 4. I guess I'm just picking knits (did I spell that right), about Harden getting burned and Lee's bad help defense. That could still be a problem, but after being proved wrong on Pierce by IP, it probably isnt that big of a concern.