I started a progression server so... Here's another thought that came to mind.
There is sorta friendly fire in this game, it might be made in the 90s but the complexity is great. Most spell casters target the enemy and use a spell on it, but a few classes can use rain spells where you target something and fire or magic or whatever will rain on that area in 3 waves. It hits the player themselves and can kill them, and it hits any enemies, including ones that were supposed to be put to sleep by your team. So you can wake them up and they will then aggro you or the guy who slept them and maybe cause your group to all die. So most people don't use rains... You can kill yourself if you are not far enough away, or if the thing you target with the rain, then runs at you... it is scary. Many newbie Wizard has died that way. And often with a group, someone is mezzing stuff, so waking things is deadly too. But the mana/time efficiency of the waves of damage are so strong, if you play as a duo or a group that has a plan and can work with it, then it is awesome.
People being able to kill themselves with magic is something that vanished from MMOs, which is sad. Also waking mesmerized targets should come back. I was so disappointed with WoW and later games when they did the turn into a sheep thing. In EQ you put the enemy to sleep and any damage at all will wake it. So I used to get in trouble with my Necromancer, I was so uber efficient, I sometimes would cast slow but long lasting poisons on a group of enemies as they are approaching the group. The group piles in and ganks them one by one, and while they get to the 3rd or 4th enemy, it is mostly already dead thanks to me. But if someone is sleeping targets then I can't do this or it could kill us all. (They sleep an enemy, a second later it is woken by my poison and it is super pissed at me or the guy who slept it and kills them, and sleep wont work and the tank is expecting it to be asleep)
Same goes for rains, and other area spells. Often tanks or melees or someone would throw a few attacks at targets before they find the target everyone is focusing on. It always helps to do bits of damage and if you are tanking then your hits are creating aggro which is good. But this would wake mezzed mobs often too, and could kill everyone. So the game forced people to play in a slick way. Everyone learned that you had to all assist one person. I remember being in a life and death battle and the group were already fighting like 5 enemies, and me and the Enchanter were at the side and had another big enemy to deal with. It was fighting my pet which is why me and the Ench weren't already dead, but the pet isn't capable of tanking it. So I see he starts casting his mez spell and his character turns to look at me. If I didn't do anything his mez would land, my pet would instantly wake it up and the mob would change targets to kill the Enchanter for trying to mez it. That would be really bad. And that's usually what would happen. But I played a lotttt and I knew the guy and I saw him turn to me too which I will always remember
I just wait a second and then spam my "pet back off" button before the spell lands, and we are safe.
But this kind of tense interaction between real people, in real time, quick intense decisions and stuff... On the internet, in the 1990s, that is so amazing to me. It shows how gameplay is king and even with the low tech, it still gave plenty of room for great gameplay. Now the tech is so much better but the gameplay has degenerated.