He suffers from something that affects a lot of people apparently. I call it "the not doing jack shit syndrome" or "familial Mediterranean fever". That is when for some reason, somehow, a player has around 25-50% less spells used than people doing decent DPS (ranking high most of the time).
I theorized that this is due to simply not understanding a fight and reacting to what you see. This will destroy Destro DPS. It's the reason why I'd say it's one of the harder specs in game to master. You simply can't be reactive, you have to be proactive.
If you have to dodge from a spell when you have 0.5 seconds of a CB cast left, you either not dodge (take damage, deplete healer mana) or you cancel your cast and for Destro, difference between a buffed Chaos Bolt and unbuffed are simply insane (for me it's 59k vs 110k). You could avoid that choice by knowing what will happen in the next 10-15 seconds in the fight.
For example on Imperator, it took me around 5 attempts to understand the correct add and trap spawn sequence for Phase 2. That allows me to cast 1 extra Chaos Bolt 3 times that fight even though a trap is under my feet. It is because an add dies and pushes people away before the trap activates. There's not enough time to finish the cast and run away but there is enough time to finish the cast and be thrown away
He barely touches the adds. I know it's hard as a warlock, depending on the add my Chaos Bolt might still be traveling when the add dies however there are ways to work around that and it's extremely beneficial to DPS them:
- you can target the add when the spawn animation starts (when he's still a cloud on the floor)
- you should manage your resources and have 2 embers for each add
- due to how fast adds die, I found that the optimal way to do things is Havoc before the add spawns. This accomplishes 3 things: 1. Havoc will copy a Chaos Bolt; 2. You will not lose time trying to put Havoc on Imperator while the add is low causing you to probably miss the Shadowburn; 3. If you are good enough at it, you can copy 1 Chaos Bolt and 1 or 2 Shadowburns because you can have 2 Havocs on Imperator for the same add
- CD's are very good to pop for adds. Add dies faster=> less healing required=> more p4 mana for healers. You should get 1 Chaos Bolt and 1 Shadowburn at least for each add and that translates to a lot of damage (Havoc CB, Havoc SB, 1 more CB generated by casting and 2 more CB's generated by SB; if you play your cards correctly, you will do 5 CB's and 4 SB's within 20 seconds)
I didn't play the fight properly myself on our last kill because of the holiday break and the raid being basically people talking and laughing but still, here's a few spell cast differences(our kill was 11:11 and your best attempt 10:13):
Me: 54 CB's, 50 SB's, 158 incin, 81% uptime Immolate, 46 Conflagrate
Yw: 24 CB's, 9 SB's, 144 incin, 92% uptime Immolate, 44(47 hits) Conflagrate
The Immolate uptime is also pointing to (besides different strategies) to simply inefficient spell usage. He's using Immolate(a 15seconds DoT with cast time) on THE ADDS. Not only the transition adds but the Aberrations that should die almost instantly.