I'm not going to get all down on the team just because of one loss where they pretty clearly forgot what it was that got them in the playoffs in the first place, but this is the reason there were so many rumors about KP trying as hard as hell to get a point guard through trade. Blake is a bit like Joel in that he'd be the best backup at his position in the league if that was his role, but thrust into the starting lineup he's got some deficiencies you can't quite mask against an elite athlete like Brooks and especially against an elite defensive team like the Rockets.
Then you have our backups:
Bayless has the elite body to match another opposing point guard stride for stride on the defensive end, but his offensive game is so raw and un-NBA ready that you can't count on him to be out there either
Sergio has elite passing ability, but not the strength to fight through picks, or to prevent post-ups from bigger guards so he gets pushed around and in a starting role wouldn't be able to prevent an opponent from getting to their spots.
Look on the bright side (such as it is) the playoffs are going to reveal this team's warts in full living colour, and give KP a pretty clear idea of what needs to be addressed in the off-season -- this is where we find out who they are.