I wish that VEAI had an Avisynth plugin as it would simplify my workflow. Avisynth frameserves a frame (or field) to VEAI’s engine, VEAI processes it and then returns the processed frame to Avisynth. The full complement of options would be passed in the Avisynth function call for VEAI.
I can understand creating the GUI as you have done simply for the reason that an Avisynth plugin by itself would not likely generate sufficient sales, but adding the plugin would be relatively simple IMO (I’m an experienced programmer).
The plugin might even work in Windows 7 without any change as the GUI would not be used. That would speed up and simplify my workflow.