>>50763380Grass is not as omnipresent as water so it would improve them somewhat, but only the rock types that are already good, the bad ones still get fucked unless the weakness to water is specifically their problem (very few cases).
For example you'd think aerodactyl and archeops improve but boltbeam weakness is far more of a problem than scald weakness. Even if they received neutral damage from it, it's still decent damage and a chance to burn.
Shuckle appreciates having one less weakness, but it's nothing that will make it jump in popularity. Rock/water types gain a resistance which is particularly good for the special attacker ones (so omastar). Coalossal and magcargo have an easier time existing, but still die to ground so who cares.