That isn’t any different on the C15 – there is nothing on the C15 that cannot be edited directly on the hardware unit. A web-based visual editor CAN be used (through the C15’s built in WiFi), but it isn’t necessary.

I think the key thing is that you can do any editing you want to do on the keyboard.

As a C15 power user, the things I would definitely want about the C25 is the built-in polyphonic aftertouch keyboard (C15 accepts it from an external source); the four additional CV ins; the audio inputs (just for mixing purposes); and maybe even the shorter touch strips (the C15 touch strips cover the entire length of the keyboard, and though the resolution is great, it’s too far for practical use). I also imagine the C25 may be lighter and simpler to set up – the C15 in the case with all of the accessories is HEAVY, and the control part of it has to separately attached to the keyboard.

Anyway, anything that keeps the Phase 22 synth engine in development is a positive sign to me. It’s a dream for those interested in synthetic feedback and exploring the harmonic series.