I think that's going to be about it. The knobs, an optional expression pedal, or an optional 3-way auxiliary switch set transmitting CCs, or a pitchbend message. But that's only considering the routing and components that you've mentioned. I can think of some possibilities with a MIDI event processor (to translate from one message to another), but that would still require a few more devices in the chain to make it useful.
If you have this particular Doepfer module, then it must be part of a larger modular system (at least an oscillator, filter, VCA). Maybe it's a full-blown A-100. With a module like the A190-2, I would run a sequencer (or even a cheap MIDI keyboard controller) through the PitchFactor, and then into your modular synthesizer [changing OUTPUT from XMT to THRU].
The value of such a routing would be in sending the MIDI notes, velocities, pitchbend, CC messages to the Doepfer system to use as gates, triggers, variable CV voltages, etc. At the same time, the CC messages and pitchbend could be 'borrowed' by the PitchFactor for synchronized effects.
This would be especially effective if the audio output of the Doepfer system was processed by the PitchFactor. But it's an equally valid routing to have another instrument processed by the PitchFactor, and have it 'bound together' with the A-100 system by virtue of similar, synchronized movement.
Don't get me wrong: Life would be easier here with sync via MIDI Clock. But I can still see good possibilities in combining these two devices (PF and Doepfer) together.
