Part of the problem is the depreciation of resource management in favor of cooldown management and GCD mechanics. A better balance could be struck. This would add depth to player skill and strategy. Allow for more epic fights and crowd control or pulling mechanics could become deeper strategies.
Mythic guild skill is a reflection of player skill. WoW has hit a wall with efficiency mechanics. Burst mechanics that use resources would help sort of combat this. Where people would need to learn where and when to expend their most expensive abilities and how to recover for the next time they are needed. I want to be clear, I’m not advocating a return to classical mechanics. Not at the solo level. Just consider striking a balance.
The weakness of long cooldowns is there’s no resource attached other than a static timer. Granted some class abilities can effect this, it’s just not that dynamic though.
Which brings up another level of complexity. Bosses always run the same abilities the same way and phase the same way. Maybe for example phase a boss somewhere between 60% and 40% depending on RNG. Or depending on how fast the first 40% of damage was taken. As one simple example. Or have different mechanics interact. So if adds are killed a boss uses a different ability than if adds are kited. Maybe if all the adds die the boss pops into a dps check bubble. If kited the boss will make a random add explode. Or target an add with a heal which could be interrupted, and than the adds could die at a later time safely with the boss at 50%. This would let guilds pick and choose strat a bit and go up against different mechanics. Maybe a guild with one comp would choose to kite. And another guild would go for the bubble.
BTW. I totally agree with OP. Stop designing raids or testing with addons.
<3 for OP in 5 hrs when I get more.