The league's change in defensive rules are having a massive impact on the game. There is no telling how dominate Yao would be under the old defensive rules in the NBA. He is basically being double-teamed before even getting the pass. And can you imagine how dominate Olajuwon would have been on defensive end if he was allowed to patrol the paint stepping out only once every three seconds regardless of where the player he was meant to be guarding is? I would love to be able to watch both players under the league rules from the differing eras. Hakeem would be even more of an animal on defense, while Yao would be 'unbeatable' to say the least.
Excellent post he would be like kareem. He would devastating inside the post and with his ability to make foul shots the points would just tally up.
It should be noted that Hakeem's offense would most likely suffer. Imagine Hakeem as a 21/15 guy with 5+ blocks per game. Interesting thought.
Defensively or Offensively? I don't think there is any way he would do worse offensively. If you watch the old games, another player could come over to Hakeem only when anticipating an inbound pass, and then that player would immediately have to run back to who he was guarding or get called for an illegal D.