Important to note that you CAN disable KEXT-signing to enable third-party SSD TRIM. While this is undesirable and an additional security risk, it is no less secure than previous versions of the OS that didn't enforce the feature.
I wouldn't hold my breath waiting for Apple to support your third-party SSD. They are going to use this "security feature" to extract additional licensing and control over the hardware. The current Apple direction seems to be to "appliance-iffy" everything and kill the third-party accessory market even in the Macintosh space.