And with nine months still to wait, there'll be plenty more to show off. They do the usual high level concept in the reveal, then build on top of that in future updates, and there's at least a couple of Directs worth before release.
Nintendo are the masters of detail and polish. Especially these past couple of gens.
Visually I think it looks lovely, the only thing I don't like is the sea animation on the beach but I'm sure that'll improve. The rivers look lovely, and I think the animations have been sped up a bit. UI looks nice too, much better than New Leaf.