FF is becoming our Devastate with 1 sec CD(see first tiers of talents), because of the FF thing I bet most feral druids will only take 2 talents in imp mangle, so if my maths is correct with GCD(thin FFF was 1 sec GCD and mangle and lacerate was 1.5) in order to maintian pulverise buff we would need 7.5 sec to spam lacerate(though technically due to mangle we would need like 11 sec) so either we get some gylph so that pulverise doesn't remove all lacerate stacks on target(or at all) or this spell isn't ment to be used constantly.

Anyway guess we need to wait longer for beta to see if this might get some CD or maybe lacerate stacks is reduced to 3 or something.

I'm not certain whether Boobah's or Allison's interpretation is correct, but there are interesting implications either way. Let's assume the following: there are no glyphs for Pulverize (though I suspect there ultimately will be), you're talented into Endless Carnage, Shredding Attacks and Ferocity, use Mangle on CD, aren't using Maul and cast FFF as you were pulling.

If Allison's interpretation is correct, we would most likely alternate Pulverize and Lacerate after reaching 5 stacks of Lacerate, so that we continue to get the full 3930 dmg bonus to our pulverize, as opposed to giving Pulverize diminishing returns as we spam our full stack of Lacerate into oblivion.

Again, with Mangle on CD and no Mauls, we would see our full stack of the Pulverize crit buff at 27 sec, at a cost of 292 rage (117 for 9 Lacerates, 100 for 5 Pulverizes at max dmg and 75 for 5 Mangles). After the first 28.5 sec, the rotation opens up considerably. It is important to note that, due to the duration of the Pulverize buff, Lacerate's bleed and the CD of Mangle, that you must Pulverize no later than 13.5 sec after you reach a full stack of the buff the first time (in order to keep using Mangle on CD) and the rotation requires 2 Lacerates between Pulverizes (one immediately following to re-stack to 5 and another before the next Pulverize to keep Lacerate from falling off altogether).

A rotation like this would result in 4-5 free GCDs of every 10 to use for Maul, Swipe or whatever the situation and your rage income dictate.

On the other hand, Boobah's interperetation has it's own implications. If Pulverize consumes all Lacerates on the target, then we can see a full stack of the Pulverize buff after 10.5 sec at a cost of 115 rage (65 for 5 Lacerates, 30 for 2 Mangles and 20 for one Pulverize). However, we immediately incur another 95 rage cost (and 7.5 more seconds or 7 GCDs) for re-stacking Lacerate while keeping Mangle on CD, bringing the practical figures to 210 rage over 21 seconds.

While this scenario yields the full stack of the Pulverize buff much faster, and at a slightly lower rage-per-second (10/sec vs. 10.25/sec in the previous scenario), the fact that Allison's interpretation gives us 5 max-dmg Pulverizes and maintains at least 4 stacks of Lacerate is pretty significant.

The minimum use of Pulverize to maintain the buff in this case is one every 10 GCDs, and it would never interfere with using Mangle on CD, nor would we have to worry about making sure Lacerate didn't fall off because 5 of the next 9 GCDs would be spent re-stacking Lacerate. However, after we take Mangle into account, we're left with a rotation that has 1-2 free GCDs every 10, very little uptime for a full stack of Lacerate.

Obviously, glyphs have the power to change all of this. A glyph that kept Pulverize from consuming Lacerate would make Boobah's interpretation of the Pulverize mechanic more desirable. Unless such a powerful glyph is in the cards, then I hope (and have to believe) that Allison's interpretation is the correct one, as it's hard to fathom the designers' intent to be for us to spend the majority of our rotation stacking a bleed and seeing it at full power for ~3 seconds despite its 15 sec duration.