As explained already, there’s an effect on the player base as queue times goes up. Eventually, there will be people who will adjust the split in the player base on their own, simply because they want faster queues. In other words, there’ll be people who will stop queuing for shuffles as a DPS and others who will reroll healers to queue for shuffles, which will bring the queue times down that way.
Different rating ranges got different splits in the player base for roles as well.
The real problem is that healing isn’t seen as enjoyable in a heavy burst meta, so it points more towards core issues in gameplay design which Blizzard will be forced to address eventually.
However, tanks have no place in deathmatch PvP. It’s just a shame they didn’t disable the ability to queue as that role completely, but this is good enough for now.
Also, there will be tanks who will reroll to prot palas if they aren’t playing that already, because they’ll want tank queues. So they’re not gone entirely, it’s just limited to prot palas now.