I’m sure this has been suggested before, and I know the arguments back and forth. Yes those of us on large population servers did this to ourselves, but we don’t want to leave our communities behind. I propose a simple solution, a two-way transfer.
Currently the mega servers have free transfers to less populous servers, but people are reluctant to jump on it. Simple solution: anyone who uses the free transfer gets a one-time use ticket to transfer BACK to their original server, from the new one, that expires in a set number of days (say 24h before the server-first titles for raiding are available). So if I transfer from Benediction to Sulfuras, at any point in the next *** days I can transfer back, regardless of how big the population on Benediction is. Those with active passes are counted as part of Benediction population so the realm stays “full” to allow everyone to come back if required. If the pass expires, tough luck.
There will be some number of people who get stuck - oh well. There will be some number who like the new server and stay - bonus. And a lot of others will port back, but it will be after the one-month chads finish their level ups, post that they are sick of the game, and quit until the next major patch.
This rids all the arguments of not leaving a server since it is only temporary, it alleviates the queue at the times where need is greatest, and the absolute worst case scenario is that a month from now everything is back to the way it is now… The population of the new server will grow if only a little which is still better than nothing, and the $$$ bonus for Blizzard is that a set number of people will miss the free transfer window and can be offered a paid transfer, if cash is the incentive required for change.