They’ve given their reasons in the same post that informed players of the free character migration.
Initially, Chaos Bolt was made because of overcrowding on the PVP realms. I sternly advocated not to do so, because I knew the following will happen:
Now the CB realm and Lava Lash will be merged with other realms to create a better, cohesive realm. But I don’t think it was a good idea to create it to combat “queues” in the first place because it will lower later as expected - this happens everytime when a new toy/game mode occurs.