This is not accurate. The 6% AP loss is inconsequential at best, and barely even noticeable at worst.
Factor in the loss of 6% AP and now maul & mangle are nerfed roughly 20%, everything else more like 30%.
You're ignoring the fact that Mangle was nerfed for a reason. It did too much damage.
To revert, the buff should have been 25%: 9600*0.25 + 9600 = 12000
That was pretty much the goal.
* loss of about 1.5-2k dps single target
A "missed" mangle will have a slightly larger impact than before, yes.
* harder to generate threat in the start of the fight
This has more to do with retarded DPS not understanding how threat works.
* overall loss of about 6-10k TPS in the first 30 secs or so of the fight, giving some heart-attacks for when the dps start popping their cd's.