Stallbreaker Haxorus is fun to think about, yeah, but it still gets laughed at by Prankster abusers like Whimsicott and Tornadus, and some of the more notorious Ice Shard users also have the physical bulk to switch into an Outrage. Cloyster and Donphan come to mind. Also, where's the EV spread for it? I'm thinking it's going to want to invest in defenses and speed to stand up to what stall has to dish out, possibly drop Brick Break for Swords Dance to make up for the lack of attack EVs (breaking screens prematurely is always fun, though). It should also be noted that no matter what it runs, Haxorus literally has nothing in its physical arsenal that will let it muscle past Skarmory.
It's well known that Nidoking makes for an unlikely but effective special attacker this gen with a good defensive typing. This moveset abuses his wide special movepool, Sheer Force and LO recoil negation to the fullest while also providing literally the best possible coverage in the game. (Haven't used it yet, but feel free to theorymon the crap out of it.)
Nidoking @ Life Orb, Sheer Force, Timid nature (power drop is negligible, speed rules)
4 HP/252 SpA/252 Speed
-Earth Power
-Shadow Ball
-Focus Blast
-Ice Beam
According to the type coverage calculator on PokemonDB, Ghost, Fighting, Ice and Ground together misses a super effective move on only 151 Pokemon. Unfortunately for the horny one, most of these monsters fall into the bulky-water or bug-attacker category, hence why Thunderbolt and Flamethrower are listed on the on-site sets. For someone that never knows what to expect or just wants to rip Super Trains a new ass, though, they probably should give this set a chance.