levitate:
remove this ability in Hydreigon
Why? : By making it immune to ground type pokemon,
well then Hydreigon has 2 immunities (Psyc & Earth) taking it as if it were flying type starting Hydreigon has much advantage that land is not affected, while taking advantage if you can beat that can learn the Attack Rain Dance,
by doing this the earth type Pokémon will inserbible before,
this, I find it unfair,
that is vacen in Bulbapedia this means that more skills will insert pokemon:
http://es.pokemon.wikia.com/wiki/Lista_de_habilidades
pokemon does not have to have 2 immunities if not of its kind
Honchkrow this justified, that is Dark / Fly (psyc & Earth)
My suggestion: I believe that these skills are not necessary in the game, for example in Hydreigon, do this only with the more pokemon Opness
another suggestion: if not remove this ability, then the change to the use of passive movement, as a Harden, for the same duration