This is just a quick thing I wanted to suggest and gather opinions for; complete customization of Pokemon. Hear me out.
Instead of or in addition to CAP, players could have the freedom to create their own Pokemon with their own sprites, stats, etc. While these wouldn't be listed in the Pokemon list, perhaps there could be another tier for "Unofficial" CAPs. Of course there would be those people who max out everything or make incredibly cheaty combinations, but that's why it would be only allowed for Customs and UCAP. Perhaps once a month or so you could select 1-3 UCAPs that are balanced and well made to make it into CAP.
This would also benefit people (such as myself) who use PS! for other purposes besides a standard battle simulator. I personally use it very often for Roleplay, so being able to create my own characters (Pokemon or otherwise) in PS! would be an extreme plus. It would also assist Fakedex creators balance out Fakemon for fanmade games.
If server storage is an issue, why not have the UCAPs be stored locally as a set of variables. This way, only spritework would be stored on the PS! servers. While there is always, of course, the issue of vulgar images being used as sprites, it becomes one of those "Use at your own risk" types of things, similar to random Custom matches with Level 1000s. Additionally, a report method could be implimented.
I could see it as a very fun and very useful tool to mess around with, especially using it among friends or as a balance test. Testing out different typings and base stats, greatly increased potential for CAP, and a lot more recognition than it currently has.