They kind of do that already since the smoke unit ramps up at startup to get smoke production sooner.
Additionally, I had one of the first gen legacy GP7's and smoke would increase when the locomotive accelerated or the labor was increased. Not huge amounts of smoke in either case, but a noticable increase.
I'd be happy with a fan motor, that makes zero noise like the ones in my TMCC stuff.
I too, have one of the first Legacy GP7s and with the smoke, it works that way. But never was a fan of smoking diesels, so I just turn off the smoke unit on them and I'm happy. Smoking steamers: Yes. Smoking diesels: No.