There's a lot from the D-50 that's missing on an MT-32, like 50% of the ROM capacity, and all of the filters and effects.
And on top of that, DigitalNativeDance is an outlier. It was (for its day) such a profligate use of ROM that it's not even representative of what a D-50 could do, in general.
Not that this contradicts your main point about GM constraining the choice of sounds.
And on top of that, DigitalNativeDance is an outlier. It was (for its day) such a profligate use of ROM that it's not even representative of what a D-50 could do, in general.
Not that this contradicts your main point about GM constraining the choice of sounds.