As a championship contributor, Pau Gasol had better stats than Bosh pretty much across the board; more points (slightly) rebounds, blocks, better shooting, better passing, it's really no contest.
As a lead man on a borderline playoff team, Bosh has better scoring, but Gasol has better everything else, and that is before you take into consideration of pace. In 2006, for example, Grizzlies were ranked 5th in pace at 86.3, while the Raptors were 26 at 91.1, that's about a 6% swing right there. 05 and 04 were similar, though not as drastic.
That said, Pau is a lock for HoF, and yes, mostly due to his international play, but also because of his role as a championship contributor. He was, at worst, the #2 on a 2 time champion, while Bosh, will be, at best a #3. If Bosh ever gets in, it will be like that of James Worthy, but Bosh has to really step up a few tim
es in the playoffs like Big Game James did.