Regarding Depeche, people on Youtube have broken down exactly what each band member was playing during the 80s shows; you might find it interesting. The parts are simple. I don't say that to knock them at all, on the contrary it shows that pianistic excellence has little to do with great synthpop. Alan Wilder is a trained pianist and found little scope for his talents in those shows.
Of course the fast, repetitive bits were either on tape or sampled into the Emulator keyboards.
Of course the fast, repetitive bits were either on tape or sampled into the Emulator keyboards.