@FrostFollow

OK so this afternoon I switched to frost and my first impressions were... wow. Frost strike consistently criting for 3.5k (at 77, almsot 78), howling blast hitting for 2k per mob, icy touch criting for 1.5k. This is also with pretty much zero glyph help. I'll probably make myself some glyphs to see if I can make myself do even more.

I never said that frost was BAD, I always said that I just didn't like the "feel" of it, that its rotation was kinda funky. I guess that's because when I last tried it I was below the level of having obliterate, and hadn't played the deep frost tree as much. I'm actually considering leveling with frost now, maybe even using it at 80 on live.

Now compliments aside, there is a major flaw with frost. That is, that it is frost. We have already had bosses in BC that are completely immune to frost (1/2 of hyrdoss), and while I never raided naxx pre-bc, it is my understanding that Sapphiron is still completely immune to frost damage. Sure that's only one boss, but it means that you would be completely useless for that fight, and might require you to respec. I'm not a fan of having to respec mid-instance because that is just flat out expensive. Yes, they may be working on a dual spec system, but it's not here yet, and I'm thinking that it's probably months off. Until then, having a boss that is completely immune to most of what you do is a HUGE drawback, even if it does do sick damage otherwise.

I'll keep testing it out.

that's a definite plus for frost then.

I hit for about the same with an oblit as I do a frost strike. They're not really comparable though, because FS is a RP dump, while oblit is what you use against single targets.

over frost strike? It's not comparable! Frost strike is an RP dump like death coil, you cannot compare it to oblit, it's apples and oranges.

Compare frost strike to death coil. (both RP dumps)
Compare Oblit to howling blast. (both FU abilities)
Do not compare frost strike to Oblit. (RP dump != FU ability)

With it's 6 second cooldown, HB is limited to thrice per 2-cycle rotation (3 HB's requires 12 seconds, 4 requires 18, which is longer than the duration of Frost Fever, so 3 is the limit). With a single pair of death runes, you have 4 FU slots in a 2-cycle rotation, so in general, you should end up with 3 HB's and 1 Oblit per rotation. Since that Oblit occurs before the 3rd HB, though, you most assuredly need Annihilation.

Also, in general, HB and Oblit hit for about the same. That said, HB scales significantly better with attack power. Since it has a base 20% AP coefficient, it's net AP with full talents is 65.56% (0.2(Base Coeff) * 1.1(Glacier Rot) * 1.3(Black Ice) * 1.042(averaged Merciless Combat) * 2(Frost Fever bonus) * 1.1(Tundra Stalker) = 65.56% AP). Obliterate, on the other hand, has a base coefficient of 100% weapon damage, so fully talents it nets 119.2% weapon damage (1.0(Base Coeff) * 1.1(Tundra Stalker) * 1.042(averaged Merciless Combat) * 1.04(Two-handed Weapon Spec) = 119.20% WD), which equates to 8.5% AP.

This doesn't take into account the significant amount of extra crit chance on Oblit from talents, but the conclusion is the same. A static increase in attack power will benefit HB approximately 6-7 times as much as Oblit. Since HB doesn't scale off weapon damage, this difference is made up for and generally stable as you gear up, but the attack power buffs present in raids will make HB push ahead of Oblit rather strongly in that environment.

In essence, the net effect of this is to point out that HB > Oblit. As the previous poster stated, if you have an FU slot available, use HB if it's off CD, otherwise Oblit. Try to structure your rotation so that it staggers your FU slots sufficiently to get in 3 HBs and 1 Oblit, instead of 2 and 2.