Wii U can rely on the tap-tap-tap method or crib Gran Turismo's second stick throttle. It's not the same thing, but I play GTA4 on my keyboard with WASD controls just fine. Still a strange omission. The original Classic Controller still had analog shoulder buttons, but they were gone in the Classic Controller Pro, which made it incompatible with a couple games.
What was even the first game to use triggers for acceleration? I wanna say Metropolis Street Racer was the first I played. I remember finding the scheme confusing as late as when GTA3 came out on the Xbox. Nowadays it's damn near necessary since you're using the face buttons/analog sticks at the same time.