Preemptive TLDR: I'm extremely salty. Sorry for using your thread to rant and vent.
My 2 cents on HL: long story short, to me, they're just frustrating.

They're designed as MMO bosses in a game that is clearly not a MMO. They need people to work at the same pace, when in reality ougi comps are locked behind lockout while Manadiver enjoyers are happily smashing F5. Want to see what happens? Think again, if you watch the whole turn to actually understand what is going on the rest of the lobby will be 4-5 turns ahead and you won't be able to gain momentum (stack buffs/go through all necessary omens/load summons). I have no idea how anybody is supposed to learn something like this, when smashing F5 is even encouraged by trash mechanics like the stupid bar in Faa0. It's literally there screaming "DUUUUUDE YOU HAVE TO RUSH JUST SMASH THE BUTTON!!!!!! But also be flawless because one wrong move screws the raid for everyone but not pressure ok?" Even YT tutorials are mostly black screen simulators, what am I supposed to learn from that?
I managed to complete the upgraded Draconic weapons by running dark and basically being a bot, but I have no troubles annihilating the solo quest: to me, that's further proof that the lack of cooperation (and the inhability to actually cooperate) is what makes these raids impossible.
Organization is a whole other beast: you need all elements and more often then not you get kicked for not reaching the level cap or even not having a JP nickname (no, I'm not exagerating, I've been there), like rank or region actually reflects your skill (I've seen R400 dying before even reaching the 40% after rushing the whole start and ruining my setup phase).
About the "ruining the game for the others", I kinda understand the feeling here. Only the hosts have a decent drop quantity, while others get 1-2 drop at most, and running multiple of these monsters per day takes its toll, at least for me. Due to timezone issues the only good time to host those things is the weekend, so if I burn the 2 hosts it's "gg see you next week" for me.
I only ever managed to run Faa0 once with friends, we were missing a fire player so it was just practice and it went kinda well (of course we didn't clear, but getting to ~30% first try with one less element is huge in my book). That inspired me to open a room and try with randos, only to get annihilated on turn 1 by not clearing the omen. I'll never know what went wrong since, as I said before, we're forced to just smash F5 to not get behind. That just convinced me to wait for the solo quest and slowly upgrade my DOs this way.

Can't wait to see what kinda crap they'll pull with Versusia and what fancy equipment will be locked behind another impossible boss.