1) Above all, make every pet family as desirable as the others (all pets can dash, no pets have caster stats, all damage pets do the same overall damage, all pet families have a special, and useful, skill, etc) - there could be nary a single new beast in WotLK, and this would make for far more pet diversity than anything else.
2) Have scorpid sting stack. A 20% miss rate debuff on the boss would get four hunters in a raid without question.
3) Have freezing trap be more viable without the trap talents. I'm finally at the level where all I do is heroics and raids, and being forced to either take the SV subtree or tell all my party members that my cc is not reliable is silly. Mages, priests, warlocks, all the other cc classes can have reliable cc without being forced into a particular talent tree. If they get two resists in a row, it takes 4-6 seconds of the mob running around free before they're back under control. If we get two resists - the mob is free for a good 30 seconds. And that's only if the tank was patient enough to wait for the first cooldown, otherwise a single resist will ruin our chain trap.