I don’t want O2 to be super tough end game content, thanks, so please no redesigns with that goal in mind.
I think the current O2 redesign has been done well and gives a variety of challenge without being smack you on the head instadeath if you make one slight mistake (hi Nest).
Though I think I’d prefer if his phases weren’t fixed at 80, 50, 20 percent, but he cycled through them randomly in the same way that O1 does. Then you aren’t stuck with a player group versus a phase that none of them are capable of.
Having the capability to back out of the fight is important for keeping the game accessible and to stop players continually grabbing for the hack client as the only way to deal with a too-difficult game/enemy.
HP scale isn’t a perfect thing in here either at all, since leechers now negatively affect the fight, instead of being merely neutral non-combatants before.
On the side, I always thought of O1 as the actual boss, and O2 more as a bonus level rather than O2 as the Final Form or anything.