Let's see how well it actually does before we go on about how brilliant Apple's marketing guys are.
Yes, the iPad has potential. It doesn't make sense to dismiss it offhand just because some of us might not have a use for it.
No, not every single Apple product has changed the world, even though they're all introduced as revolutionary. It doesn't make sense to accept their marketing copy as gospel. Lots of companies pay lots of money for sentences like that, it doesn't mean they're all successful.
Ultimately, the market will decide this one. Yes, it MIGHT change the world, but it really is too early to tell one way or another.