Based on what Nintendo mentioned at the last Direct about different combinations of ARMS I don't mind if the character amount is low.
10 characters with 20-30 different arm type variations is plenty.
My biggest concern are the non motion controls. Everything I've seen has emphasized the motion controls first making me think the standard pro controller setup may be an afterthought.
The marketing for this seems to be great so far. With the general positive buzz around the Switch, as well as this having some breathing room around its release window, I could see this being a big hit.
