I refer to the sig of somone that said:
Whenever I suggest a garchomp counter there are rocks, 3 spikes, t-spikes, sand storm, garchomp has 6+ atk and his moveset is eq,dclaw,outrage,draco meteor, stone edge, and fire blast.
This is obviously exaggerated but the same applies to skymin. It can't have sub/seed/hp fire,ice,ground,fighting/seed flare/air slash and growth all at the same time. It can also not hold yache, life orb, and specs at the same time either. That would be an uber poke. But since it can only run 4 moves with one item, it is wallable and revengable therefore not uber. Especially without playtesting!