>>46310691Rubber as a type wouldn't do jack shit to help out the current type balance.
Types that do well against it are strong enough already as offensive coverage for Fire and Dark or are already decent neutral coverage for good Pokemon under Steel. All it does is incentivize more use of such coverage and mons with that coverage and doesn't ensure that Dark and some Fire types, who need a booster shot, will be used.
The amount of defenses is good, especially with Fairy, but in return it continues to lobotomize Bug and Grass as viable types/coverage, when they already struggle in the current meta, and strangles Grass's niche by being a better Water resist.
It's super-effective coverage, while not horrid, is generally covered by Ground astronomically, losing incentive for common use. Along with that, being resisted by nearly half the types drops incentive for coverage as well since good coverage covers a good amount of types if not all types. Even for Ice, which desperately needs more resists, wouldn't get much use from resisting Rubber because only Rubber Pokemon would want to use those moves, which based on that movelist, isn't very diverse.
