Having a digital modulator in an FM synthesis drum machine makes the sound no less analog than digital envelopes or the digital LFO. If having a digital sine as modulator for FM drum machines is what needs to happen, I am perfectly fine with it. I agree that the analog modulator gives a hairy grit to it, although for things like cowbell or hi hats I think the digital edge on a modulator would give the analog signal some glossy sheen.