You'll forgive me for being confused about your positions after reading your later sentences about the ARR endgame fight design being worth less money (???).
Ramuh stuns require counterintuitive cures. Shiva cleaves kill non-tanks and walls imprison you. Nabriales Triple Spark kills tanks and time dilation rewards clever buff usage. (old)Moggle Mog's raidwide wiped if you ignored adds. Ifrit nails kill if ignored. Relic Hydra casts untelegraphed puddles and Hysteria AoE. Leviathan add casts Hysteria if ignored. Sophia add's ice puddle kills if not off-tanked out of the way. Bismarck is mostly an adds fight. A5N kills unless you stop DPSing and devote yourself to some mechanics. A6N is all about irregular AoEs. A9N adds must be moved and killed correctly. In A10N you can set off AoEs if you're not careful.What content in Raid/Trial roulette doesn’t fit that criteria you listed? This goes back to even ARR Hard mode. The “tankbusters” are cleaves that tickle, the raidwides tickle, the safe spots are still obvious, the boss stands still auto attacking for an entire minute, some adds pop up and sometimes you can ignore them completely. This is how all normal fights play. Not asking for any more encounters like this is asking for no more encounters at all. And the thing is, making it any harder than that will make DF groups disband because a wipe being decided by a curebot is not fun when you want to go through dailies.
It's not about being easy. These fights are still easy. You can explain the mechanics I've mentioned with a single sentence before the pull. Nobody disbands for them. The mechanics are different and non-formulaic because the devs were still trying to make them different.
Who is 'us'? You got a mouse in your pocket? When a sprout asks me about Coils I offer them congratulations on having great taste and invite them to one of the Discord servers that runs synced Coils daily.I understand you want fights to be less monotonous, but level 50 is not the place for that. You are no longer new to the game, so this stuff is boring and easy for you. But sprouts have not played through ShB and EW yet. They’re being told by us, “Oh yeah coils is actually way harder than all the other raids just don’t bother playing it synced for now” and the only 8-player content they have reasonable access to is primals. There is nowhere else to learn to play with a co-tank or co-healer. That’s why I want normal Coils.
Level 50 is a perfectly fine place for content to be less monotonous, it's actually equal in importance to level 90 because there are so many more new players at 50 to be impressed by the quality. Nobody's impressed by new 6.0-style Copperbell Mines when the boss winds up for a 5-second tankbuster cast and then hits for barely more than an auto-attack, and they're not learning anything about tankbusters either.
Sprouts literally have all the content in every expansion to look forward to. They're not suffering for lack of 8-mans upon hitting level 50. Most of the new players I've accompanied through the process actually want less sidestory content to do in post-ARR because they're excited to get to Heavensward.