I just wanted to start a thread about this
I watched TESB yesterday, with all the prequel movies (and ANH from past week) in mind. And it rocked.
As some here have already said, Darth Vader simply can't do acrobatic moves. He uses raw power. Although it doesn't show in his Obi-Wan duel, it does in the duel with Luke.
I just observed, and Luke got served pretty hard. At the first strikes Darth Vader disarms him. It's just that Luke jumps in time, because Vader already leaps (jumps) in on the disarmed boy! Luke is then bashed into the carbon freezer which he only escapes by luck (jumping into the cables at the ceiling which Vader can't reach).
At this point, Luke is already tired, haird al sweaty, bruised eye sockets, almost limping. Vader then just toys around with him...the scene with the window and bridge, etc. You can also clearly see he only uses one hand to fight in the duel, not even using his full power.
With Episode 3 in mind, It wasn't that bad! Vader really looked lik the strong and powerfull Anakin, although in a much different way.
But alas, the episode 6 duel...isn't that nice...and neither is the episode 4 duel.