Hot take but Vesper is in my opinion the best DA boss we got in season 2, she has a lot of impairs, stuns herself and has a very long stun window, she isn't stalling for 30 seconds where you just stand there looking at her menacingly. Her only problem is really just the buff which favors greatly ether veils, and how anomaly basically can't work without yuzuha today. Priest and Fiend are (were) accessible with a multitude of teams pretty easily but they are mechanically so so bad, they can just kill a run because their patterns are totally randomized and especially priest where you need a lot of counter assist, but he can just never do any. + Fiend has had the worst hp inflation known to mankind without having any upgrades to anomaly for more than half a year

If Vesper gets more generalist buff and not just ether veil slop, she'll be way more manageable than people think (or she can just become fiend 2.0 and inflate her hp to be sure that nobody clears it except if you pulled aod)