Mod FX is one of the best-sounding effects in Logic. Perfect pads, pianos, even drums. Separate it from Phat FX, give us a few waveforms to choose from (triangle, sine, maybe even sample and hold?), plus another LFO to modulate the rate of the first one. Maybe a dual system option where one stereo input is modulated inversely, like Ringshifter, and a stereo detune option to make some really fat-sounding stuff.