I did get a chance to see the Prototype at NAMM and am VERY excited about this device. I can see a pretty wide range of my customers (and ME!!!) using it as our primary control system not only for guitar rigs, but laptop based control of all sorts of audio and video systems.
The biggest advantage I see to the GT is those LCD displays above each button. For those who are concerned about being able to read them in a live environment, remember that the text on an LCD can be as large or small as the display itself allows. That is, each display COULD only show 3 letters if you wanted them to be really large, or multiple lines of text if you didn't need the size. I do agree that anything we can do to make these displays larger would be great. I'd suggest perhaps looking at some of NTTs new OLED based displays and perhaps even their OLED switches.
I'd also like to see a footpedal unit that uses SILENT, or at least very quiet switches. I know there are several manufacturers who make heavy-duty momentary switches which look pretty much like these standard pedal board switches, but are actually quite quiet. Having switches that make a significant "CL-ICK!" sound is awful when you are playing a quiet gig, or are switching presets between numbers. Sure, it doesn't matter at the Superdome when playing for 40,000 people, but if you intend to use this in conjunction with acoustic musicians, or at wedding gigs, or church gigs.... silent switches are important.
"Mathusula2" suggested an assignable expression pedal. I don't know if you saw this or not, but there are actually 6 expression pedal inputs on the back of the unit. That's plenty for me, and I'm an expression pedal freak (love em!). In fact, I'd really like a little break-away version of the LCD display that I could mount near each expression pedal which would display what each expression pedal is assigned to at any given time. I'm envisioning a little 2x2x2 box that connects to the back of the Mastermind GT in it's Ethernet based expansion port, and has a LCD display on top. You would simply program these "Expansion Display Modules" in the same way you program the display under each button. That would be ENORMOUSLY helpful.
I also agree with "ifailedshapes" in that a larger central LCD would be nice...but I do want to keep the text on each one of the button LCDs.
The ability to use one footpedal board to control everything, and to have the labels of each of the buttons and expression pedals change with each "preset" that is recalled would be the biggest single advancement in usability of footswitches that I have seen in....well.... pretty much forever.
Keep it going! I REALLY want to see this product come to market soon! I'll shout it's praises to the high heavens if it's even half as cool as I expect it to be.
That's my 11 cents worth today.