Some sort of adjustable attack delay that would allow the Pitchfactor a bit of extra time to process the notes would be at the top of my list.  While the Pitchfactor has a ton of unique and fantastic-sounding features, the polyphonic tracking isn't anywhere near as good as it is on the Electro-Harmonix POGs.  Those pedals have a very slight delay (maybe 10-40 milliseconds) which I imagine allows the DSP to process the notes a bit longer and thus the better tracking.  I'd gladly give up a small bit of attack time if it meant better polyphonic tracking.