Well, actually the skull model itself is a good example of a cap that is pretty damn hard to make with a mold. There's a cavity inside of it that lets light through the back of the keycap and leaks through the eyes. It's probably not impossible to make a keycap with a large cavity through the middle in the way that I have it, but it certainly would be quite challenging.
I'm generally trying to make more intricate designs instead of cloning what might already exist.
If damage during replacement is the primary concern, it would certainly not be hard for me to just place and remove one of my keycaps a few hundred times with a keycap puller.
Also, I could easily just reassure people by offering some type of warranty on the keycaps where if any part damages during normal use I just send a replacement.