The reason the MIDI Solutions Pedal controller works is almost certainly it's slow processing speed. A close friend of mine who designs and implements custom performance solutions for a big Vegas show said they had to dump their MIDI Solutions Event Processors because they were too slow for the needs of the show…funny that in this situation that same slowness is a feature!
That wouldn't be a fair conclusion to draw. The Event Processor converts up to 10 MIDI message events in a series protocol, with up to 32 event processes in the EV Plus (including processing of variables). Three keyboardists playing with polyphonic aftertouch.
I use an EV Plus under my 'board, fed through a MIDI router to my PitchFactor and/or H9. I've seen what you're reporting when feeding a Stompbox with – for example – a cycling MIDI LFO, or a worn out encoder sending jitter. Not so much from a DAW [Sonar], MIDI keyboard controllers in general, or an FCB 1010 (often processed by the MIDI Solutions Event Processor Plus).
Come to think of it, I don't recall having those results using "double" precision 12-bit pitch wheels. But your experiences will have me revisiting just how hard I can push MIDI through the Eventide 'boxes. In the home studio, I usually have a MIDI Monitor open in the background. It should be easy enough to correlate the data throughput with visual & audible feedback.