Hello,
I would like to request new feature in cluster environment - ability to specify new BalancerHost during sh.startBalancer().

For example, I have cluster made of number of replicaSets. Each replicaSet have backup servers inside, with priority 0 in order to do only backup job.

It would be also nice idea to make priority levels also working for electing as BalancerHost in the cluster instead of specifying exact Balancers.

Thank you,
Maxim