What about make it so in addition to ignore abilities, they also ignore resistances, and Immunities? And/Or make them Mold Breaker + Burn/Paralyze versions of Corrosion.
It doesn't really make any sense, and this is just compounding several abilities into one, which Gamefreak avoids of doing. At least with the ability nullifying thing, it is an upgrade over mold breaker which extends on the concept, much like full how metal body is an upgrade over clear body and how shadow shield is an upgrade over multiscale (in that they cannot be ignored by mold breaker or sunsteel/moongeist/photon)
The only "compound ability" I can think of is Water Bubble, which on top of reducing fire damage by 50% and preventing burn, doubles the BP of water moves.
Another thing, may I add, when thinking about potential new abilities, is that not every ability needs to have an special/physical counterpart, or for other types. This allows certain typings or certain category of walls/attackers to be distinguished, and increases gameplay diversity within the game. So, I strongly think there should not be special versions of fur coat, huge power and intimidate, for instance (just like I believe a physical assault vest would be dumb, even if it makes sense), nor do I think there should be too many -ate or -worker (though that one could work for 1-2 other types) style abilities, etc.
Also, about potential new abilities, I think drawing a parallel to Gen III is interesting, as that was when weather causing abilities were introduced. It came with a few weather based abilities, but most of the abilities affected by weather came in Gen IV. Therefore, I think it is extremely likely that we see more terrain based abilities like grass pelt or surge surfer, though not necessarily to the extent that we saw in Gen IV with weather abilities since terrains already offer a bunch of additional effects compared to weather.