Z3TA+2, a fantastic synth, supports a great variety of wiring between sources and controls. The current interface, while largely visual, is visual only at the level of each module (oscillators, LFOs, effects, et cetera.) In what follows, I refer to the connection of one module (the source) to another (the destination) as "wiring" rather than as "patching" so as not to overload the latter term's meaning.
A system level wiring graphic, with blocks only for each of the modules, could help the user to understand a patch/program at a higher level than is now easily possible. If several sources arose from one module (say the LFOs) with multiple destinations, a graphic (e.g. "LFO1") could clarify the wiring. It could be useful in reconfiguring a patch, copying parts of a patch to a separate program (including, if more than one module is selected for copying, the wiring between the modules) . And it might be useful as an alternative graphical presentation of Z3TA that one could choose (a wiring diagram). With such, one might be able to bring up any of the patch's modules (e.g. LFOs) for editing as pop-up dialogs that could be dismissed back to the system level graphich when the editing had been completed.
The first generation analog synths were painfully obvious in their wiring: the user had to wire patches between modules. As a suggestion, popping up such a graphic might be accessed with a right-click on the modulation module. As a possible approach to achieving this graphical interface, one might look at some systems rendered in Visio, together with the back-end VBA that automates its graphics, as a start.