Hi
My 2p in the 'nice to have' column
1) Controller/Midi change for input volume. This would allow one to use a controller pedal, midi control pedal, and/or software as a volume pedal before the unit – thus being able to produce some nice swell effects.
2) Increase the max speed (mod rate) in the mod delay to 10hz (or more) – this would let you get it up there to create some nice leslie type effects.