"I'm not digging obliterate at all anymore, for any spec.
It's just very much overshadowed by the other things every other tree offers as a replacement for that spot in the rotation.
And to be honest, I'd rather see obliterate become something other than a 'super blood strike that removes diseases' at this point.
DRM rotations as blood won't/don't use it because there aren't enough supporting talents in blood for it anymore, now that MoM doesn't affect it. Blood has an overabundance of blood runes via DRM, and this directly translates into wonderful synergy of sudden doom, bloody vengeance, abom's strength procs, along with better RP generation, as well as more attacks from DRW while it's up.
Frost will never use oblit if HB is ready to go, and even if I can't use HB, i'd rather use icy touch for 20 RP and similar damage for one rune. Not only does howling blast do more damage, but it only requires frost fever to do max damage, ignores armor, can AOE, and doesn't remove the disease. It's just a no-brainer.
Unholy has Scourge strike, which is also a no-brainer to use over oblit in every single way.
Without blood talents (read: DRM and MoM) supporting Obliterate, it's simply a bad skill that doesn't fit in anywhere, for any spec right now."
Now, with all that being said, I'd like to bring something up that I've brought up in the past:
I'd like to see death strike reworked a bit and make it cost 1 blood rune instead, and tweak it's effectiveness to go with it.
1) It feels clunky as a 1U1F cost. I like my finisher being HB or SS as frost/unholy as is. Death strike with a 1U1F cost as frost, which is very disease independent (outside of frost fever) always feels incredibly weak. The choice should really be between obliterate and the tree-specific finishers. Thus, obliterate needs to be reworked a bit to be a more universally powerful and useful ability that is independent on spec.
2) As Frost: Using blood strike as frost for blood of the north feels like a chore and isn't fun. There are many times I'd rather sneak death strikes into the rotation instead of blood strikes to catch up on healing a bit rather than do a bit of extra damage (again, if it cost 1B instead). I'd rather have the choice in the rotation be between blood strike and death strike. In a group scenario with a healer? Blood strike for more damage. Healer CC'd or solo and need a bit of extra healing? Death strike instead for that part of the rotation. Then, use a finisher. Ideally, blood of the north would cover blood strike, death strike, and pestilence.
3) As Unholy: Using blood boil and pestilence for reaping is fun and all, but again I'd rather see options for single target "combo" abilities to build up those death runes to make combat more fun and engaging. I'd like more choice in the build-up process for working towards those death runes/finisher moves. Again, it would be nice to see DS use a blood rune for unholy rotations just the same. You want to do AOE damage? Blood boil. Need a bit of extra healing? Death strike. Ideally, reaping would cover all of these abilities as well.
4) More choices = More fun. I think it's been made quite clear by several parties at this point that spending 33% of our runes on blood strikes half of the time (especially as frost) is not fun.
5) Death strike heal amount is very underwhelming unless it crits. This plays very well with deep blood specs that A) Have lots of blood runes, B) has a higher crit chance than other specs, and C) includes both vicious strikes and MoM. Blood would be a lot more fun if you had the choice of doing a lot of damage via heart strike in DRM rotations, or by using DS to heal yourself with those blood runes, which would further lend itself to blood being the self-healing tree. To go along with this point >
6) Obliterate would then need to be reworked into Death Rune Mastery, and have death strike removed.
7) Make Obliterate more friendly to use. 125% weapon damage and doesn't remove diseases? Generates 15 or even 20 RP per use? Obviously blood would want to use it with these changes over the other specs due to DRM, but why would the other specs want to? Shadow-resistant target? Don't SS, but oblit instead. Can't AOE? Use oblit instead, but make the damage worth it, and remove the disease-removing penalty.
8) Rework annihilation to have your blood strikes have a chance to refresh the diseases on the target, making the choice between death strike and blood strike tougher. Blood strike is simply boring right now, and this talent would really make things more fun and interesting. I'd also probably have it refresh the disease on the current target when pestilence is used as well. Right now you have a half-assed way of getting around this, by applying diseases on a target, then using pestilence, then tabbing to another target and using pestilence again (refreshing the diseases on the initial target). It just feels clunky to do it this way.
Edit: (I forgot to clarify this part) Then, I'd move annihilation to the blood tree, and give us a reason to sneak in 1 blood strike during the rotations with those overabundance of blood runes so that you don't have to use icy touch + PS again (which are just awful damage by themselves as blood spec). The idea here is to give you an abundance of blood runes via DRM working off oblit, and using one blood rune per rotation for a blood strike (or pestilence if AOEing) to refresh diseases. This essentially frees up the need for epidemic as blood, as well as lets you get off another oblit than you normally would, solidifying obliterate as our finisher move for blood.
9) Rework Death strike healing amount if it being a 1 rune cost is too much. 50% healing per disease? 75%? 1%? 1000%? The numbers are easy to play with, but I'd probably reduce it to 50-75% or so.