As the primary Ground-type users generally rely on either EdgeQuake (Excadrill/Landorus) or DragonQuake (Garchomp) coverage from my readings, the ability to only take neutral damage from each is fairly good. This thing shouldn't be weak to Exca's coverage moves.
Acrobat+Fling Gliscor is problematic, but this is predictable enough IMO.
Secondly, it gives it good coverage, and a typing niche.
EDIT: A flaw with Water/Flying: Yes, Excadrill wouldn't want to switch in, but would Thundurus?
Last edited by Tortferngatr; Mar 8th, 2011 at 6:22:16 PM.