Seeing as RO used to have it, there could be contests for selecting which ones are included. It can be changed every month or so. The standard informative loading screens could still be used as well along with the fanart ones. This would give a sense of connection with the players and the game.
Yes I’ve noticed TOS seems to try to come across as more serious theme and with a consistent look that random art might not blend with, but if so, the art could be used around special events or holidays. The screens can revert to the normal look when there is not an event.