Being hard to switch in isn't as big of a liability as previous generations. Why? Because with Volt-Turn, or even just ScizorWash alone, you can get free switchin's into a prefered target relatively easily. Just look at Terrakion: he is a pokemon that is hard to switch in but dominates the ladder. He gets paired with Scizor and Rotom-W so often because those two provide free switches to get an attack off. You really didn't have the ability to get free switches like that in DPP without Volt-Switch threatening those who resist U-turn.
So expect Haxorus to paired with Scizor and Rotom-W (who already work phenomenally in rain) a lot for those free switches. Sure Haxorus takes down only that one Poke that gets it the most, Skarmory, since any other path would be two down's for your side instead of one. But you won't be in a good spot dealing with that CB Scizor. This isn't even considering Magenezone who not only can remove steels, but get Haxorus in safely. Having the 3rd slowest (meaning it uses volt-switch last) and hardest hitting Volt Switch out of all of its fully evolved users, it can get it in safely making it a really good partner.