We are still missing a very good and reliable shotblocker. Yao is foul-prone and he is an average shotblocker. Scola and Hayes are positional defenders, not shotblockers. Mutombo is our best shotblocker but he will barely play. Shotblocking is huge in playoffs. Rockets have enough in other areas that they can mask this defeciency, but if they had great shotblocking to boot, this team would have the potential to be great.
I dont think shotblocking is huge, overall defense is huge for example: the Bulls with Jordan never had a very good and reliable shotblocker, and that team were great, they had a good defense and offense, but not a reliable shotblocker.