Increase the number of name reservations but leave it 3 per server, you may get them to at least try grabbing names somewhere else that way.
Or start a new server that auto-reserves all the names of all the people who already have them on another server that’s overpopulated (like Herod), but give like a 48 hour period where you have to delete them off of the other server or they will auto-delete off the new one.
That way they don’t just have reservations in both places and you’ll keep a more accurate idea of which places are overcrowded.