As it stands, you have to wait 15-20 minutes for the elevator to switch between levels. This silly, and takes WAY too long. It would be easier if we could just change what the next level was on our own instead of waiting. Each switch would require more and more minerals and resets when you descend to another level.
Instead of this being moonstone exclusive, I'd prefer if you had to use a handful of whatever minerals the stratum you're currently in instead. This means if you're trying to level up a battle sprite you are more likely to suffer through a level you may not like as much to avoid using your minerals, but if you have an abundance then there's no reason you can't use this to switch.
This kind of idea plays off the old "gate building" idea we had before battle sprites were introduced.