I would love to have 2 features that I use constantly with my nord modular G2...
1. patch mutator: be able to take 2 patches as "parents" and interpolate them to make "children" patches that are a cross between the 2 parents. ideally, you could sweep between the two patches with a MIDI CC
2. variation storage... have each patch be able to hold a number of variations, that can be called immediately. I tried using program changes to get this effect, but it wasn't fast enough (16th note program changes didn't always change fast enough)
for instance, you could have a bass patch, and there could be 8 (or more!?) variations to that patch. perhaps variation 1 is staccato, variation 2 has a slow attack, variation 3 has a bit more distortion etc. you could assign velocity to the variation, and each note you sequence, depending on it's velocity, would play a different variation.