how exactly have pet special moves vs. players been nerfed already?
I think you're misunderstanding something here. The only thing that has been nerfed is pet speed for pets with overcapped dex (190+) and overcapped swingspeed. In other words a single pet has been nerfed, namely the phoenix. Everything else stayed the same.
This special moves nerf adresses a PvP issue where certain pets could teleport next to you and instantly kill you if the special moves and their other abilities lined up perfectly. And no player should be able to instantly kill another player, no matter if he uses a pet, a weapon or a spell for it. That's why WoD got nerfed for PvP back then, that's why AI damage was capped for PvP etc. etc. etc.