There are plenty of good apps already that let an iPad edit or create office docs. Ultimately the real constraint to that is form factor, which is why I think apple have it right in positioning a tablet as a consumer of content and not a creator.

Notebooks and laptops are plenty light enough that it's no hassle to carry both. Most of us do exactly that when travelling for work and I can't see it changing. It's the ecosystem that determines success now and it's going to be hard to displace the credible lead apple have here.