There is one thing they could do but probably won't, outside just gating it that is, and that would be to provide incentives for playing on said dead or new DC continually...damage buffs, gil, etc. That is one way to grab attention and interest...could be by influx hours too. Just message each DC when there is a low population on a specific DC so people can see and join that dead DC, this would allow queues to go smoother and might also build community given people would flock to said DC just to get the rewards, this would allow you to see familiar faces