One of my favorite dropped features from the G1000 (I presume the EM2000 had the same) was the ability to easily (no sysex) modulate vibrato speed as well as depth from the aftertouch.

This actually is what most real players do, it’s rare to find someone who’s vibrato stays at a precise speed as they increase or decrease the depth. Light slow vibrato gradually changing to a bit faster as it gets stronger is very common in the real world.