Healer queues taking longer than usual?

[HPDelron]

If lot of people stopped playing tanks, and they'd distribute evenly among dps and healer, that'd still hit harder the healer queues since there is half of the spots for them comparing to dps.

To Illustrate, here is a gross simplification:
Original Player Pool:
100 Tanks
120 Healers
300 DPS

100 parties can be made. 20 healers Waiting. 100 DPS waiting. No Tanks waiting.

Half the tanks leave and go evenly to Healers & DPS

New Player Pool
50 Tank (-50)
145 healers (+25)
325 DPS (+25)

50 Parties can be made. 95 Healers are waiting. 225 DPS are waiting.

The pool of waiting healers is close to 5 times bigger. While the DPS pool has only about doubled. Granted matchmaking is more complicated than this and the healer/DPS excess disparity probably isn't quite that huge (though this would make things worse, not better for healers post-exodus). But you can see that an exodus of tanks to other roles will always disproportionately affect the healer population unless they skew heavily DPS.