I agree that it would be in this CAP's best interest to reduce the number of type threats in order to improve playability (despite the concept saying we shouldn't cover the weaknesses). Reducing the threat of Water-types would go a long way to giving this CAP a major niche of other Fairy and Flying resists. While Psychic from Manaphy will still be a problem, even the reduction (or removal) of Scald as a problem will go a long way to improving the match-up. And this vastly improves its match up against stuff like Azumarill, Keldeo, Rotom-W, Politoed, and Tentacruel. This provides a quality niche of being able to check all of Talonflame, Keldeo, Azumarill, and Clefable all in one slot, which nothing else can do. One of the interesting factors of this typing was that it received a Special Defense boost from Sandstorm, so we might as well embrace that when looking at threats to this typing. Since Hippowdon is likely a better partner than Ttar, a reduced Water vulnerability helps deal with a major worry, without too drastic a reduction of weaknesses. Note that this doesn't require a Water-immune ability either.
Mitigating or removing the Ground-type weakness is a step too far imo. In the end, Rock/Poison had a majority vote, even though everyone was aware of the massive Ground weakness AND the fact that Ground moves were one of the most common form of coverage in the OU metagame. Having a way to threaten Ground-types might be in order, but this typing does threaten Pokemon that use Ground coverage (Mega Altaria, the Mega Charizards, Mega Pinsir, Mega Aerodactyl) so it's not exactly helpless. Counters don't have to be passive, as long as they have sufficient bulk (the +100 bst boost will help a lot). Posing an offensive threat to some of the Pokemon that counter the CAP right now would go a long way to improving the CAP without actually diminishing the weaknesses too heavily.
Mitigating or removing the Ground-type weakness is a step too far imo. In the end, Rock/Poison had a majority vote, even though everyone was aware of the massive Ground weakness AND the fact that Ground moves were one of the most common form of coverage in the OU metagame. Having a way to threaten Ground-types might be in order, but this typing does threaten Pokemon that use Ground coverage (Mega Altaria, the Mega Charizards, Mega Pinsir, Mega Aerodactyl) so it's not exactly helpless. Counters don't have to be passive, as long as they have sufficient bulk (the +100 bst boost will help a lot). Posing an offensive threat to some of the Pokemon that counter the CAP right now would go a long way to improving the CAP without actually diminishing the weaknesses too heavily.