I think it depends on the usage.I'm a bit surprised how little attention is paid to the controller end. Surprised Even a stock Voyager is capable of a truly infinite pallete of sonic textures, but most "keyboardists" play one like a piano or organ, or confine themselves to midi programming alone as the means of creating sound.
People that play synths as keyboard instruments often use them for melodic lines.
The fact they can make endless sounds isn't terribly important to the context of their work, but being in tune and sounding good is.
A pop or hiphop song is not always the best vehicle to demonstrate textural diversity.
A trance song or tone poem isn't the place to show off a funky bass line.
Whether a person creates a million interesting sounds or plays a preset one finger at a time, I don't think one usage is more valid than the other.
Instruments and music are personal things and not everyone is Wendy Carlos, where both keyboard chops and sound synthesis come into play in large way.
Some people just want a good "worm" sound in their track.
Some people buy Porsche turbos to then drive them only 35 mph .
That's their business.
As for lack of controllers, the Voyager would seem to be the least likely synth for such observations.
It already has a multi-axis control pad, aftertouch, lots of knobs, jacks and two wheels.
No other analog synth has all that and the pad *was* Bob's idea.
It would be really nice to have a keyboard with keys that modulated from side to side, but there's no one making them and no large market to fill.