Actually, depending on which game you are playing this on, liquidation is better (slightly ) than waterfall. Waterfall is 80BP while liquidation is 85BP and still activates the Sheer Force ability by having the potential to lower the target's defense.
Also, I personally agree that Ice Punch is nearly unmatched in terms of coverage, but in terms of damage, earthquake technically does literally 1% more raw damage. It's preference.
Ice Punch and Dragon Dance are both egg moves, crunch and liquidation can be taught by a move tutor in USUM.
Hope that helps!