Well I think the strategy for Aegislash is best to take a hit, then attack, then King's Shield, and rinse and repeat. Its defense is too shit in Blade forme.
In regards to the speed: might actually be better to go lower on slow things, in case someone tries to pull trick room on you. I'd guess it's pretty much that or try to speed tie other Aegislashes. Actually, since steel doesn't resist ghost any more, that would probably help most. Even with priority, you'd still run into that speed tie.
With the general strategy for that guy: How do you get the King's Shield off though? Does it have priority? If not, I think you're better off just doing what you can with Shadow Sneaks. Unless you know you can resist or something. I need to look in to how that guy works more.