A 2 year turn around is absolutely unacceptable in this day and age especially when half the time the only “feedback” they seem to take on board is how popular the content is as a means of determining whether to keep it rather than actually taking onboard the content of the feedback
If a piece of content had 3 seperate releases (say criterion, savage, alliance raids or piecemeal content like IS) they should be ready to iterate on the feedback for the second iteration after getting it for the first. Not waiting till the next expansion to maybe fix the problems if they decide to keep that content in the next expansion
Aglaia being horribly undertuned should not have doomed euphrosyne AND thelia, they should have been ready to pivot to fix euphrosyne