The biggest division was always the "dps stance/cleric stance bad" and "tank stance/healer stance good" camps. The way Yoshi-P wanted the system to work, and the way players from other games wanted the system to work were at odds.
This is how we lost interesting emergent gameplay mechanics in fights as well. Players figure out the best way to minmax DPS when they were NOT supposed to be doing that, and thus parts of the fight end up skipped or the boss dies too fast to get to them.
Would I like to go back to exactly how ARR or HW Cleric stance worked? Nope. That was an awful system because OTHER PLAYERS would demean you regardless if you used it or not. How should it have worked? Well if the MSQ was designed to actually care about what class or job you had, and not assume DPS, maybe jobs could have been designed to be interesting. But they can't, the MSQ does not let you play a tank or a healer in "tank stance" or "healer stance" the way it was originally designed.
How do I know? Because I played the entire ARR MSQ without using Cleric Stance in 2.0. It sometimes took multiple tries just to do some of those "talk to NPC, spawns enemy" quests. That's how far apart the DPS you did as a healer, and the DPS an actual DPS did that didn't have to do extra steps, when an actual DPS could knock that enemy down in 5 seconds. Tanking was pretty much the same, but had the advantage of not being as squishy from the armor.
What would have made this all moot was removing Cleric Stance and Tank stance and instead having that "built in" to the content. When you play these "solo" contents, it should have been from a "role play" setting, where the game expressly requires you to use your job skills (eg healing, tanking) to complete the instance. Even an express "DPS Stance" , "Healer Stance", "Tank Stance" switch would do this, where entering multiplayer content forces these switches on, and when these switches are on, you are supposed to use tank or heal, not DPS. When the content decides you are required to DPS, it then turns "DPS Stance" on all players. But for this to even work, there has to be things the healer is REQUIRED to heal, that are not always the party members, and likewise things the tank must pull enmity away from. That would require changes to all the content in ways that might not be fun at all if you are playing a healer or a tank, where you might be required to do something boring, while the DPS get to fight. It does not make sense in many pieces of the game for there to be friendly players tailing you, so why would a tank or a healer need to do anything but help their party?
I think that's where the question of DoT/HoT and other types of buffs matter, and we've largely lost most of them, due in part to how DoT ticks consume a lot of network bandwidth. The game would need to re-engineer how buffs and debuffs work, and that can be solved by having the buffs be one-time casts (eg like how Protect worked) that drop after a fixed amount of time or when cleansed, or one-time uses (like stone skin.) Same for debuffs. It's just unfortunate how most of the debuffs cast on a player can not be cleansed, and those that do, can usually just be ignored because the longest buffs are typically 1 minute. Imagine if the buffs and debuffs lasted the entire fight.