With VW seeming to be all about saving cash these days and their move away from building three door models, I can’t see a three door mk8 ever being built, as it’d require three door-specific new body pressings, windows, interior panels, seats and probably many other three door specific parts. All of this would involve extra cost, which goes against VW’s current cost cutting, cash saving approach.
I think the only three door car left in VW’s current model line up is the up!, and I’d expect the next generation up! to be a five door only - that’s assuming there’ll be a next generation up! It’s sibling - the Seat Mii is now an electric-only five door and it looks as if the Skoda Citigo is no longer built.