In an earlier post I talked briefly - hinted, really - at whether improved mangle is really all that now that swipe has been so significantly boosted. What I found out was pretty surprising to me.
Yes, I'm using the teaser trailer. Bear with me. :)
Pre swipe getting boosted, the best threat rotation for a bear was mangle, lacerate x 2, with a faerie fire thrown in whenever it was off cooldown or when it was applicable (stupid misery bug...). This meant that in an 18 second window, you would mangle 4 times and lacerate 7 times and faerie fire once (hopefully), along with 7.2 mauls. This would result in the following, assuming AP of around 5k, a crit rating of 40%, and the standard talents you'd find in most tanking builds:
Damage(lacerate DOT): 815.1
Threat (mangle): 3406.9
Threat (swipe): 1578.763 (post 50% boost)
Threat (lacerate): 1162.154
Threat (maul): 5309.797
Threat (Lacerate DOT): 844.21
4 mangle/7 lacerate rotation: 66991 threat, or 3721 TPS.
If you take out the improved mangle, you instead get a 3 mangle/8 lacerate rotation. Basically every 18 seconds you go to 65746 threat, or 3597 TPS. That's a loss of 124 TPS. That sounds substantial until you look at it as a percentage: it is only 3.35% of your total threat.
But that's not the rotation any more. The rotation for best TPS is now swiping whenever the cooldown is up and throwing in a faerie fire whenever the cooldown is up.
This assumes using the same 5000 AP and 40% crit from above.
Using the same methodology above, we have the following
4 mangle/7 swipe/1FF rotation: 64842 threat per 18 seconds, or 3602 TPS
3 mangle/8swipe/1FF rotation: 63014 threat per 18 seconds, or 3500 TPS
Net loss is 101 TPS, or only 2.8% total threat.
2.8% threat really isn't that big a deal in the long run. It essentially means that improved mangle is worth about 1% threat per talent point, which puts it ahead of master shapeshifter but behind rend & tear. The above is also the best case possible; it assumes you're mangling every time you can, that you're not using berserk (which helps the non-improved mangle case more), and it discounts rage/healing gains for threat.
The first surprise that you might have is that these numbers show that lacerate, not swipe, is the best threat. But...didn't I just say the opposite a couple weeks ago? Yep. The main reason is that that calculation assumed a 30% armor reduction, which is a bit unrealistic. 40% is closer to the mark. With that and a low-ish AP value (5k is pretty low for raiding tanks), lacerate wins out on threat. If you instead have 6k AP, swipe wins out again. So I was still right...it just means that if you're on the lower end of gear, spamming swipe for threat is not as good as lacerating.
Okay, you ask, what about the best damage case? Since a lot of people seem to care how much damage a tank does, we'll go through with that. Using the same 5k AP/40% crit, the cycle for optimal damage is something like:
mangle whenever it's up
lacerate to keep the stack up (once every 12 seconds)
So in a 36-second cycle (we need it to be 36 seconds to fit in the lacerates), we have the following for max dps:
+36 seconds of lacerate DOTs (12 ticks)
The damage for that is:
60624 damage, or 1684 DPS
For the same cycle without imp mangle, we'll have 6 mangles, 3 lacerates, 15 swipes, 14.4 mauls, and 12 ticks of lacerate. That damage is:
58351 damage, or 1620 DPS
The loss of DPS: 63.1, or 3.74%.
That was really surprising to me. It does mean that improved mangle is a really big bang for your buck in terms of overall damage - it's better than the 1% damage/talent point that the devs have stated is something of their goal, for instance - but it's not so big that you can't live without it. And do note that as AP increases, both the threat and DPS loss from imp mangle also increases. At (for example) 10k AP you're looking at a 3.9% DPS decrease and a 2.9% TPS decrease. Which isn't earthshattering, but it is something to note.
To me, this solidifies what I've been leaning towards for a while: improved mangle is a nice-to-have but hardly an essential talent. And it's one I'm going to drop, in favor of picking up more cat-friendly talents.
Curious about my numbers? The spreadsheet I used is over at google. The numbers were from EJ's feral values here and here.