Tough question.
Stuff that isn't just clones of older circuits.
My own thoughts:
Unique stuff.
Brian from Smallsound/Bigsound commands my attentions (and my finances) due to his unique designs and their defining, well thought out features. Aen from Dwarfcraft and Ryan from Dr. Scientist hold my interest due to their well built and often odd options. The dudes from Wilson Wahs I like because they expand upon vintage circuits whilst keeping quality high and prices down.
Boomerang got me to buy one of their Phrase Loopers because of its huge functionality and lack of features I won't use (I like to do everything live. No prerecording.)
That's why the Strymon Timeline doesn't appeal to me any more. I'd use 3 settings on it. So I bought an analog delay and am shooting for an El Capistan, because of it's useful features and the fact that it's solely a Tape Delay emulator.
What i'm trying to say is, make the pedal simple, deep (as in versatile) and good sounding. I think a lot of the guys around here like one box per effect, (otherwise we'd probably be more into the GT-10's), but for that effect to be of a high sound and build quality, have something on offer the many, many other effects like it do not. Make it easy to tweak, and sculpt sounds out of. Make it good.
Don't build yet another TS-808. Don't build a Big Muff. Don't build a DS-1.
A decent looking unit never turned a buyer off either.
D.o.S. wrote:Personally, I'd like to see a "melting AM radio" style distortion/overdrive pedal.
See? Something that isn't on offer really. Great idea by the way man.