Yes, Pierogi is definitely behind the curve right now in supporting source controls in detail. There is the "Input" button on the Utility panel, which is useful if your target device has a single button that can cycle through all the available input sources. There is also an "Input Panel" you can activate, that has a handful more source control choices.

But yeah, I do want to set up a more comprehensive input control system in Pierogi. The big problem I have right now is that different manufacturers have made very different choices in how to manage source control, and I haven't been able to come up with a good "universal" mechanism to support them all.