Case in point: I really wanted to have two filters setup, and assign the expression to sweep the filter blend. Then I could have an envelope Filter 1 setup for heel down, then sweep the blend to a LFO based Filter 2 for quick switching between two different filter sounds. That'd be awesome! But I cannot do it.
This is already on our list of things to look at: to make the modulation matrix more flexible. It wasn't in the initial release because we didn't want to scare people (having three knobs on a Wah pedal already scares some people!)
Some things can't be modulated smoothly because it is an analogue effect, unlike a digital effect where it is possible to control everything smoothly (if it's coded correctly).
For example, the filter mix could be modulated, but it might have small clicks/pops when this is done. This is because the control is done via digitally-controlled pots which have a stepped response to them. So, we didn't allow this to avoid complaints about these clicks. However, this has been asked for, so we may add it at some point with a warning about the possibility of clicks.
Other ideas I'd like to try:
* Envelope filter but with the expression also controlling cutoff and resonance.
How would this work? Maybe as an extra layer of hi/lo for the cutoff and resonance? So, the envelope filter normally goes from the hi/lo values you set, but the pedal lets you move between other hi/lo ranges? So, essentially, there is another dimension in the control.
* Envelope filter with expression sweeping some specific range of the Sensitivity
This is planned for a future update (probably the next one). We think it will be a cool feature. You will also be able to similarly set hi/lo limits for the punch, attack and decay parameters all controlled by the pedal.
* MIDI Clock beat division sweeps while also controlling cutoff and resonance separately
Similarly, this has been requested a lot and is on our list.