Queue times can be improved in many ways. That "should" not be "the" issue, and if it is, there are other "problems".
If it has such a big impact on queue times: Change the system to an Opt-In, and encourage people to Opt-In for more BGs with better/more rewards, or favour them with queue preference and other stuff. This way players have a "real" choice if they dislike more than 2 BGs, with an appropriate payoff for their negative impact on queue times.
Seems fair to me, and I would start blacklisting deepwing gorge and SoTA in addition to AV and IoC.