There's a couple issues with that technique that worked for me when soloing. It doesn't really work in a party because (1) you might have other people pinning/KBing auf away from you, and (2) the issue with Guardian. Generally when in a party I still try to just barely stand inside auf and most likely I won't hit her right due to iframes from the previous non-sed hit, however with how the map is laid out and her hitbox size, that can cause me to get stunned, meaning I can easily die to seduce since I'm inside auf. Potentially extending her touch hitbox a bit could work, or extending the platform on bottom left, or making her not able to move quite as far left would help. Making Guardian KB a toggle would be nice too. I wouldn't want it to entirely go away as I do use the KB when pinning auf.
I agree that could work on soloing but doesn't really work in pt, (and mostly of the times I run auf i dont have another person to pin/kb auf) and I don't think worth to risky try to do it to not get dispelled And about this (not part of the topic so I'll just say quickly) I agree, I wouldn't want it go away also, I do use the KB aswell and i think is super good, thats why I don't think is a problem of the skill but is a problem of the boss.
I used to solo Auf daily before I started mage farming and I never really had a problem aside from my bishop not being able to survive a run. I did BM + NL + Bucc + DRK + BS. BM and NL attacked the same time with one hand each on PC + laptop. Dispel wasn't usually a problem during Auf aside from my BS dying. My Lv 200 NL and BM both had reasonably high avoid to avoid dispels most of the time but I'd imagine lower level ranged or sairs would get owned by constant dispels. NL just needed booster + shadow partner + shadow stars and my BM would bring +4 red arrows from showa and just use MW + SE when dispelled. As for sed I never really had problems because my NL and BM were 28k and 24k HP respectively but if I usually encountered zero issues because I would keep Auf in the middle. If you're a lower HP ranged you might need to keep Auf in the middle and jump attack to avoid getting hit by touch damage while being sed.
We will continue to review feedback related Auf here after she was made auto aggressive in Update 92.