Moves or abilities that should have happened, but didn't because fuck logic.
HARD MODE: No Shell Smash.

Also moves that some Pokemon get that make very little sense.
HARD MODE: No sucker punch. (The original name roughly translates to surprise attack. It's not a punch.)

Mightyena doesn't get pursuit.
Vibrava and Flygon don't get bug buzz.
Jumpluff doesn't get spore (Balance reason though).

Venomoth gets Poison Fang.
Whiscash gets Dragon dance,
Cryogonal gets attract (Which will always fail because it lacks a gender).