I hope SE moves the old Extremes back into the DF. It's nice having the option to queue for the current Extreme with Raid Finder instead of needing a premade but the move seems to have hurt the queue times for the old ones a lot.
I'd guess the longer queues are due to lack of awareness of the existence of Raid Finder, the Raid Finder being pickier about the jobs being matched together, and the Raid Finder splitting up the players in queue between those looking to clear and those looking to practice.