Not at all. All MA terrains use the same tilesets, so if you change the tileset you pretty much just have to press "rebuild" in the Terrain Editor. Maybe not even that.
Nope, HTC said that there'll be different terrain styles with this update. Pyro said that NDIsles is Pacific based.
On top of that, I'm pretty sure that this is a complete rebuild of the terrain system, not just a new MA tileset. I've never seen anywhere near that kind of resolution with current tiles, and the way it blends doesn't look like tiles at all.