I think that cramming too much stuff in one unit is aside the point.
It is SO easy to get effects of all kinds nowadays, I would leave that stuff out.
There are loops to achieve this and I would dedicate the effort towards the core idea: Tones.
A front face with knobs is the ideal. Works faster. And MIDI storage just makes sense.
You can always decide not to use the MIDI banks if you will...
For owning all the incarnations of ADA preamps, I've been secretly wishing to have such a thing as an MP-3:
-Keeping the 3 original channels of the MP-1 and adding the Clean Tube and Brown Channel of the Classic.
I still have a soft spot for the original MP-1's Clean Tube channel which covers such a lot of ground, from clean to classic rock tones.
-Onboard noise gate
-Original MP-1 Chorus (Not a must actually, but the MP-1 Chorus is too cool)
-Recording outs with cab sims
Assuming that ADA would put the money into quality components to make the thing as quiet as possible (Unlike the MP-1 at high gain settings), I would trade off happily bells and whistles (That I can add with loops) for basic performance, great wide quality tones that can be trimmed and stored around.
By making a simpler unit, it would help it being competitive on the market.
I think we all buy tube guitar preamps to get great natural tones...and for wahs, effects, verbs and shit, there is an array of choice
out there already. No need to mess with that.
My 3 cents...