@shellfritsch has rightly mentioned that this is the place to follow along. However, I just want to clarify something about ‘registering interest’: interest, right now, mainly serves to confirm that this is a thing that people would like and act as a kind of cheerleading for the little team plugging away at it. But when something is available to purchase, there’ll be something more formal than a forum thread 
In the meantime, your interest is always appreciated.
Regarding functionality and feature-creep: it’s unlikely much will change between what you’ve seen. We’re fettling the firmware as we go, obviously. But the form factor is pretty fixed: it is deliberately the size of a 128 grid. If you wish, for some reason, to mount 52HP of sliders in your Eurorack, I suggest taking the (eventually) open-sourced schematics and making your own project.
Remember: this will be open source software, hardware, everything. If it’s not to your liking, everything you need to alter it will be available.