I think it depends on the strategy and the pokemon role on the team.
Like Fiery Dance over Fire Blast for Sp.attack boost on Volcarona. Or even Rock Slide over Stone-edge on terrakion just to avoid the chance of missing. (even though rock slide always fail to OHKO/2HKO, and no crits :[) Fusion Flare over Blue Flare on Reshiram to avoid miss (in sun, it doesn't matter really. both still deal huge damage) Surf over Hydro pump Keldeo, and other similar cases.