Yeah I suppose you have a point there. The current Tablet PCs aren't that close the HPCs. But I was talking in context about having devices running the PPC platform possibly competing with Tablet PCs. If MS lets PPC platform run on something like those SimPads you're all getting, then it gets pretty close to Tablet PCs.
The "core" is that way to cut costs, for lower pricing. If they put in any applications it'd add too much support costs. However I do believe more compatibility with PPC apps, esp if it's not a supported "feature", would not cost them much.