No Ice Climbers.
Fucking dumb. Extra dumb if due to pandering to the shitty 3DS hardware.
WHERE'S MY CUTESKIMOS
What other reason would they be cut though?
Sakurai vaguely commented on this early on, but fans were saying that in no way meant IC weren't gonna make it back. Unless they are unlockable (doubt that), then they are gone. The writing was on the wall, and frankly, I do not see them making it as DLC unless they were free.
I'd like to be wrong though.