Create some option to do a consistent backup of config + shards at the same time. Preferably this would be initiated from a single point (mongos while no balancing is going on) and would hit specified replica nodes in each shard/config replicaset/MS (if they are RS/MS) to reduce the load on the live system.

In a multi-node cluster it is important to take a consistent snapshot in time that can be restored.

Oh, yeah, and there needs to be a restore options as well.