Just found a twitter response from GC about "beast slaying"
@Ghostcrawler Hi ^.^ Will the troll racial "beast slaying" be nerfed in 5.2 or will the beast bosses in ToThunder not count as beasts?
@HaninozukaUK They count as beasts, but honestly they're early enough in the tier that we're not super worried about the "troll advantage."
Guess this means they will not be nerfing it then, woot trolls ^.^