I think Anakin would've taken Luke out, but you'd have to ignore the fact that they're family. Or at least they would. Or it'd probably go like it did in ROTJ..
A reason I think Vader and Luke's battles weren't as fast paced and all that skillful LOOKING, is because they were both trying to turn each other, and/or maim. 🙂 But that's mostly due to the blood ties, so they'd have to ignore that to take each other out..