My sense of logic wants to compare the addition of SAM and RDM to the addition of ROG/NIN.

We did see an influx of new players who were rolling ROG. Tanks and healers left the job to try their hand at ROG. Wait times almost tripled (about 10-12 minutes to 28-35 minutes was my experience).

It didn't take more than a week or two before a lot of DPS got sick of the bad wait times and decided to roll tank or healer until things settled down. Thus reducing wait times overall. Most tanks and healers got sick of ROG (and the wait times) and went back to their mains. New players came in and some of them became tanks and healers.

I want to say - within a month or so - things started to level out and get back to what I felt was normal.

Also, PotD didn't exist back then. PotD is going to go far towards relieving some of the pressure the DF will experience from the inevitable DPS zerg rush.