With the arrival of Patch 3.1, one frost-talent got a very interesting change.
"Unbreakable Armor: Now grants damage reduction instead of physical damage reduction. Cooldown increased to 2 minutes from 1 minute."
What this means is that when I am in frostpresence and pop Unbreakable Armor I am immune to all attacks hitting for under 1300 for 20 sec, possible to increase futher by having more armor and/or glyph for it.
Even if you would have 400 mobs on you, all hitting for 1200 each you would be 100% safe during those 20 seconds, this opens up possibilites. I
The downside of the change is the cooldown, two minutes, but I have never been one of those hardcore farmers. I gather everything I possibly can at a spot, kill it, read some on the internetz and wait for respawns. If you, however, aren't one of those persons there's nothing saying you could do some single-target grinding inbetween or whatever you desire to do.
Spec: Anything goes tbh. The vital talent is unbreakable armor, from there you could go whatever you wish but I would recommend picking up deathchill and Howlinglast for awesome aoe damage, and Hungering cold just becuse it's a nice way to spread frostfever and gives some breathing room.
A normal pull goes something like this:
1. Mount up and ride around in frostpresence, gathering mobs up. Try to circle around some so that you get them as tight as possible.
2. Dismount and wait for mobs to get within 10 yards. If you just pulled 3000 mobs all incomming to hit you for 1k each this would be a good time to Unbreakable armor, if not that I suggest just letting them hit you for awhile until they've all gathered up.
3. Hungering cold(costs 0 rp glyphed, applies frostfever to all targets) and gives you some(10 sec) breathing room.
3. Unbreakable armor, deathchill, Howling blast and from here they're all(if asuming normal 80 mobs) at 50% and you can do whatever you want until another Howling blast is up, 20 sec is plenty of time.
4. ta-dam, you just killed 1 to infinite mobs not loosing a single healthpoint.
This 'rotation' isn't really needed tho, you could just gather them up unbreakable armor and do whatever you wish for 20 seconds as long as they're dead by the end or you're about to get served ;D
I won't share any spots, simply becuse I haven't found any really good ones yet. If you have, please share them!
It needs to be a spot with as many(pref melee also) mobs as possible tight together, since pulling 10 or 1000 mobs in practice wouldn't make any difference since you're immune to their damage anyway.
Have fun beeing Unbreakable