I suppose this is rather late, but my impression of ARMS is that. . .I am far too uncoordinated to actually play the game as intended, LOL. I got grabbing down pretty easily, but I had almost no idea how to actually move so the instant someone wasn't right in front of me it was pretty much game over. That and as I feared I'm just kind of bad at 3D fighters in general, most people were just plain better than me even motion controls aside and I imagine a truly skilled player would destroy me outright.
For some reason camera controls are the most motion controls I can usually handle. Any implementation different than that and I crumble to pieces.
Don't get me wrong, though, I played the whole hour. I mean, it's free, why not? I do think the arm extending mechanic actually makes it more accessible than a normal 3D fighter would be, dealing with a closing gap between characters isn't as much of a hassle as it seems like it would be otherwise. That doesn't mean it can't be competitive, though, the mechanics look like they leave plenty of room for players to become more skilled. Those players would just have to git gud at the motion controls and with the type of people that flip out at the idea of so much as using a slightly different controller to play a game I can imagine the idea of using motion controls must be short circuiting the brains of many gamers that usually go out of their way to compete in other fighters.