There's a few things they could do to fix this (at least I would imagine), have an "Unranked" Wolves Den arena which, regardless of your rank, PvP skills are not used. Yes, it goes against PvP but higher rank means access to more skills. Would also need an ilvl sync, i110 seems more than appropriate as i110 gear is no longer gated on a weekly cap. And someone at rank 45 has access to the same skills at rank 1.

Or, have a rank sync. This might be awkward as the game will have to either lock certain PvP skills or upgrades behind ranks so when you sync, it removes actions or upgrades that outrank the sync. Or do it by the earliest skills you purchase. Although then again, you have 60 seconds in the cage to prepare skills so they could let you organise your skills in that time and sync the available number of PvP skill points to the synced rank.
What they sync the rank to is up to them. Could either be that of the person with the lowest rank or round it up to the nearest value of 10 from the person with the lowest rank. Either way, Wolves' Den is just not being maintained like it deserves.