I think the point was that Obi Wan got stronger and Maul didn't. I mean, we all love Maul. But his head has hardly been in the game the last few years it seems. His obsession got the better of him. You also have to figure, theres no dramatic stakes since we know Obi Wan has to win by default. A big long uber saber battle wouldnt be very satisfying since we know the ending. What they gave us was a huge surprise, but at the same time made perfect sense when seen in the context of the characters and their place in their lives. Although I do feel there could have beena cool moment where Obi Wan tells Maul something like "Look where your hate has gotten you. You family is dead, youve lost your legs, your title and youre an old broken man chasing your first enemy into the desert. Its not too late to change". Obviously he wouldnt accept the offer to turn to the light, but I thought it would have been a cool moment, obviously done in a much more eloquent presentation than I gave.