IP - I strongly believe that Kareem Abdul-Jabbar plays extremely well vs those centers (Shaq, Moses) that you mentioned.
For the record, I've seen in several sites that Kareem weighed as much as 267 pounds. I'm assuming that that was more towards the latter end of his career, but I'm sure by the time he reached the 80s (Moses) or 90's (Shaq) he'd hold his own.
David Robinson? I love the man, but I really believe that Kareem was every bit as agile and athletic as he was - thus Kareem would not be hampered by him.
Kareem would have no issues getting his skyhook off vs Robinson.
Shaq or Moses would admittedly be able to push Kareem out some...keep him from getting to his sweet spot, but even with that Prime Kareem had more moves than just the skyhook...he could also hit the mid-range J.
In any event we have a full arsenal and variety of Bigs to throw at any threat:
Centers with more mass? We'd utilize Jermaine O'Neal or Ben Wallace more. Plus, don't forget we'd have KG on the floor (03-04 version). The fear of weakside blocks while Moses (or Shaq) are trying to gather himself up to shoot or dunk would cause him to shoot 10-15% less for his FG%.
Fear and intimidation. We have too many master thiefs, long arms, physical bodies for ANY Center to have a field day, in this format.
Plus, Ralph Sampson, in some cases, will bother folks with his length. And he would be handful offensively, too.
Just ask Hakeem Olajuwon who was his HUGE help in beating LA in the WCFs in 85-86.
Dream didn't (couldn't) do it by himself.
They didn't call HOU the TWIN Towers for nothing.
In short, Moses and Shaq would not be able to dominate vs our Bigs. They'd get a fair amoount of points, but as constructed we slow any Big Combo down out there.
And specifically for Kareem - he played Wilt Chamberlain to standstills back in the 70's...and I consider Wilt to be a dominant center in this format.
Kareem will be fine.
JO, Big Ben, Ralph, Elton and KG said so.