That's because it's not about purify, but rather how the bosses are designed. Uldyssian is poorly designed. Surely you can make him fair for melee characters while keeping ranged characters on their toes as well without the need of purify.
Firstly, he summons way too many edyrems. This is a dps check to test your clearing speed before they overwhelm you. This doesn't work well against melee characters because they hit like trucks and will put you in hit recovery animation until you die (probably). Reduce the amount of edyrems spawned.
Secondly, he teleports way too much when hit. Melee characters have a hard time keeping up and they can barely hit the guy before he teleports. What's that shit about? I never understood the need for it. It just favors ranged characters.
And probably get rid of his slow or nerf it since ranged characters can easily play against that, while melee characters will always be slowed. Also, make his stun nova be a cooldown ability rather than him casting it whenever you get in his melee range since again this is an anti melee mechanic for the sake of it.
Now that he's tuned down, buff what he does which doesn't discriminate against either melee or ranged. For example, his flower deathstrike can increase in frequency to keep you on your toes. I'm sure there are other aspects that can be improved which will not discriminate so heavily against melee characters, but saying purify is a need to balance bosses is bonkers.
Path of exile did a good job with uber elder/shaper, regardless of how much you hate it. It doesn't discriminate against certain builds (afaik). Sure, they may be too easy, but that's another problem.
Glamdring26 wrote:"hurr durr i have all best in slot gear why i cant oneshot bosses like poe"
And how's that a bad thing in an arpg, exactly? We spend 95% of the gameplay farming for items just for those to barely count in certain bossfights? Besides, you need extremely expensive gear to be able to oneshot bosses, even 120 level ones that aren't purify fights.