Of course he's not fooling anybody. My best rationalization for the subdued fighting is much better than Lucas's crappy, "One's an old man and the other is part-machine," because we've seen old men fight in the prequels, and we see Vader kick as in the other two movies. They've in a very confined space, so there's no room for jumping around like an ADD child on crack. And they are already familiar with each other's tricks, but they haven't seen each other in quite a long time. And they didn't part on the best of terms. So it's more basic rather than flashy showmanship and tricks. I mean, they're talking calmly during all this. They're still taunting each other. It's obvious they're just playing with each other for the most part.