To their credit, Source Audio has maintained a fairly consistent product-focus-- which is (or at least was) unique. They create a pedal that has a cool, signature sound, right-out-of-the-box; and the user can opt-in for more extensive customization options via Neuro. This allows different types of users to choose-their-own-adventure with their products. They've kept latencies super-low, so the multiple conversions across a pedalboard don't add up to much, and the sound quality remains excellent.
For SA to do a multi kind of doesn't make much sense in terms of their ongoing individual-pedal focus. There are plenty of companies in the multi-FX category, and that competition is pretty fierce.
When I think of what kinds of individual FX Source Audio could take on next, up until last year, I would have said pitch shift, but then Boss scratched my itch with the XS-1. So, I'd revise that to see if SA could make a really fast pitch to MIDI processor. Another option might be to create a pitch shifter that has a pitch quantizer mode that helps fretless players stay in the ballpark.
A stereo convolution reverb/cab/reso that competes with the Tasty Chips Integral would be great, and I'd probably buy it. They could perhaps integrate some tube-preamp sims and guitar/bass amp sims.
An acoustic bass sim that uses both convolution and some other tricks to simulate the resonance for pizz, and some ways of simulating arco.
If they came out with an EQ3 that had a large display, a cursor diamond with a press-knob in the center, and did EVERYTHING on pedal without needing Neuro, AND it had a stereo (or dual mono) send/returns with flexible per-preset routing options--and included high-quality dynamics processing, that would be the bee's knees.
Does anyone make a pedal that removes 60 Hz hum from singles that isn't a gate?