Hi, I'm actually one of the original MMD world creators and even made the og MMD dancepads (sdk2.0) system, which I later helped convert and shape into the newer systems. Hearing this news has actually pissed me off to the point of rebuilding my own dance world out of spite. It's still in early stages, but I do plan on making the whole system for free once polished up and converted to C# rather than relying on CyanTriggers for the moment.
(which hopefully making it free will open the floodgates to more worlds that aren't behind these god awful codes and paywalls)

If anyone needs to get their mmd kicks off in the meantime you're always welcome to share this world link with whoever and hop in whenever you please. I'll be occasionally updating from time to time when I have freetime from life responsibilities.

https://vrchat.com/home/world/wrld_319da2c6-c6fd-46c0-b665-f8a883e71f63/info

Enjoy champs