Oh god, think about it: Magma Rock (Fire type variant)- goodbye Scizor. Entry Fist (Fighting type variant)- lol Tyranitar. Wind Storm (Flying type variant)- Heracross would be even worse. I don`t think I even have to explan the impact an Ice type variant would have. Stealth Rock is enough.
But consider the possibilities of an entry hazard which could actually put an end to the abuse of bulky waters.:ching: