Between the two, Berserk is definitely much higher priority then Nature's Swiftness.
Berserk gets us 15 seconds (20 glyphed) of fear immunity and can be used while feared to break fear.
Combine that with the trinket, and this comp is pretty much fear immune, at least in the first encounter.

I've found that the 20% per combo point is unreliable with a team.
Most targets are dead by the time I have done my second move, which is 2-4 (average 3) combo points.
At 67th, I took out a solo 80th demo warlock, who I armoried afterwards (700 res) with my opening Pounce/4x Ravage.
The only time I've had 5 CP's across the board, is fighting against an Elite mob.
Granted all of this is against single targets, or once against two targets at the Hellfire Fortification; and they did not have heals.

I'm using a stance dependent macro, with a stopcasting. Trying to emulate an 'Art of War' proc, where if the cast is not instant, the stopcasting ends it. Still tinkering around with this, I want something I can spam to cast, and interrupt the cast if its not instant:
/stopcasting [stance:0]
/castsequence [stance:3] reset=5 Healing Touch,Null
/cast [stance:0] Cat Form

The Nature's Swiftness gets five guaranteed instant casts, which can be used independent of combo points. That's an instant cast Battle Rez, which with the glyph returns my toon at full health. Or its a Healing Touch etc.

Mangle counts as a bleed, and lasts for a minute.
So any effect which requires a bleed is up all the time.
You can easily put Rake into the rotation..
I've not finalized my click priority sequence, but want Mangle, Rake, and Savage Roar early, with the Kick mechanic to occur as evenly as possible.

Also messing around with Focus targets, and want the IWT/Click to target the focus if that exists or to FTL Assist if it does not.
Pretty sure, I can stick with FTL Assist, inside IS Boxer... but go with a Warcraft macro to switch target to Focus if that exists.