You seem to be doing something wrong with raging blow. Taking Nazgrim you stay on 2 stacks of raging blow for about 10 secs and you do that 6 times in the fight, that's pretty terrible. You should aim to stay at 1 stack and use RB whenever you get 2 stacks. Go into a CS with 1 stack and if the BT before CS and the BT during CS crit you get the 3 RBs you need if one fails to crit use berserker rage to make up for that.
For comparison
Pricy 42 RBs
Davski 39 RBs
Milolady 29 RBs
And it's not just more crits/procs, Davski had the same number of crits but used berserker rage 5 more times and used another 5 more RBs on top of that.
Checking the first 30 secs of the fight (see below trimmed it up a little and removed HS) you seem to be doing some things wrong as well. NINE sec gap at 20:53:05, don't think I loose more then 2 gcds when nazgrim does his heroic shockwave. During both CS you delay BT for no good reason just go BT>CS>RB>BT>RB>RB or if you have stormbolt and 2RB stacks BT>CS>RB>BT>stormbolt>RB. You have 1 empty gcd during reck at 20:53:03 and I would use reck+banner+CS at the same time.
[20:52:53.610] Milolady casts Recklessness
[20:52:53.648] Milolady casts Skull Banner
[20:52:53.736] Milolady casts Bloodthirst on General Nazgrim
[20:52:55.810] Milolady casts Colossus Smash on General Nazgrim
[20:52:57.528] Milolady casts Storm Bolt on General Nazgrim
[20:52:58.713] Milolady casts Raging Blow on General Nazgrim
[20:53:00.203] Milolady casts Bloodthirst on General Nazgrim
[20:53:01.785] Milolady casts Raging Blow on General Nazgrim
[20:53:05.093] Milolady casts Bloodthirst on General Nazgrim
[20:53:14.520] Milolady casts Wild Strike on General Nazgrim
[20:53:15.779] Milolady casts Bloodthirst on General Nazgrim
[20:53:17.282] Milolady casts Colossus Smash on General Nazgrim
[20:53:18.814] Milolady casts Raging Blow on General Nazgrim
[20:53:20.401] Milolady casts Raging Blow on General Nazgrim
[20:53:21.941] Milolady casts Bloodthirst on General Nazgrim
[20:53:23.516] Milolady casts Wild Strike on General Nazgrim
[20:53:24.827] Milolady casts Wild Strike on General Nazgrim
[20:53:26.808] Milolady casts Wild Strike on General Nazgrim