What was the last Extreme/Savage that you've done? There are places in Hades Extreme where this could be the case, but in that case it falls on the player to know that such a thing is coming and to adjust their rotation accordingly. The rotation still exists, both the players' and the boss', it's still the basis for doing damage as a damage dealer, healing damage as a healer, and mitigating damage as a tank. Your claim is coming across as if rotations are never feasible when that's not true in the slightest.
Not always, in fact most AoEs are actually quite predictably targeted. Living Liquid Ultimate for instance, you know who will get targeted by what AoE for every minute of the fight. Brute Justice Ultimate is similar, you know within reason who is going to get targeted with what, and how to pass it off throughout the encounter. Your rotation does need to be planned around what is going on, but again, the base rotation does exist and everything is just an adaption off of it.AoEs are random or are on the person dealing the most damage, or on specifically defined targets which may be YOU. And if you get targeted or it lands in your area its going to hose up your rotation, so you better be able to adapt to that.
But the mechanic will always occur at the same time every fight. Okay so tether is coming out, you know when it's coming out, you plan ahead for what you'll do if you're tethered. Base rotation, again, still exists. It's not some unfeasible, impossible thing just because mechanics can happen to you. Most fights in this game, actually, you can execute your entire rotation on without a single interruption. Also, I know no boss that gazes randomly. Name me one that gazes randomly.Mechanics may or may not pick you, so you could be the guy who got tethered which will hose up your rotation and force you to do something else. You could be RIGHT in the middle of your Trance and suddenly the Boss Mob starts his gaze attack out of a random choice so you have to turn around and again hoses up that perfect rotation you had going.
You've been playing this game since at least Heavensward, and you're blind to how scripted fights are? Really?It is not, and never has been "constant" like you're claiming.