So first off I think that most people have some misunderstanding of how the bosses in coil work they're all basically the same as players and they have CD's on all their skills the reason that the fights happen the same way all the time is that the AI uses every skill as soon as the CD is up. The reason that twin can be hard if you push at the wrong time is that as soon as it hits an hp threshold the CD for it's new mechanics starts ticking and twin always uses whatever comes up first, like delaying fireballs cause it needs to plummet or use DS. It's not about it being mechanic > mechanic > mechanic > mechanic (in coil, titan is a different story) it's just an AI using whatever is available. Btw no combination of atk's in this game can't be overcome by understanding the fight and knowing what's actually going on, though some of them can be quite inconvenience, so the player base learned what these things were and then how to force the easiest outcome.
And now for my second non-tangential point to the quote. I have literally watched vids of at least 4 different ways to do t6(briars, LoS, Super Slug, burn), 3 different ways to position the party in T7, 2 ways to handle the t7 ogres(stack, kite),6 different ways to push towers in T8, 5 different ways to drop meteors in 9, 3 different ways to handle the ghost during heavens fall and 2 ways to dodge the dive bombs. To say that there's 1 way to do everything in coil is insulting to players that come up with these strategies, and just sounds like ignorance coming from someone who has decided that the only proper way to do something is from whatever guide they read first.
You could resize your focus target bar to be massive and stick it right in the middle of your screen if you fail to realize there's a bar casting that says twister, that shows it's exact cast time, that's not an imperfect indicator it's called a lack of awareness.