Very happy with the new release!! I did an experiment running the drive on a clean amp (the Duke), rolled the volume off on a strat (position 4), and the dynamics were all there. Fantastic tone, and the pedal reacts as the best pedals in real life, very natural sounding.
This is indeed a great achievement... I have tried a similar attempt of a pedal by Mercuriall, and much prefer yours.
Now, regarding the pedalboard and the future additions, you might be entering a can of worms, because people will keep pestering you for more pedals, and your GUI will have to be able to extend or make space for more pedals very quickly if you try to please everyone.
With that being said, if you ask me, I think a treble booster will indeed be interesting and very challenging as well. There was this attempt by Rangebastard, which sounds similar to the real pedal with low gain, but if you turn the boost way high, it just shuts down everything, so you cannot really get the gain level you need for a proper Brian May tone. I personally love a treble booster on tube amps and would love to see what you can get from it.
Other suggestions: a graphic EQ to shape the tone from the drive pedal (as you have in the Wayfarer, but more bands), a tremolo (as you have already in the Wayfarer), and a clone of the classic MXR Flanger, which nobody has been able to accurately recreate in a VST format.
Congrats Mike! It keeps getting very difficult for me to use another amp sim, because nobody has come close to what you have achieved.