I'm in two parts about this. As someone who fenced, and a HEMA enthusiast, and the like, these fights should be fast. Swords are not just I-beams swung around and getting slow or tired in a fight is one of the prime mistakes to losing that fight.
But because the old trilogy established that Jedi aren't supposed to be flashy mass-murderers and duelists on speed, when it comes to Star Wars, I err with the 'old guard' of the thought that these fights are supposed to be calculated, that their practioneers are very old veterans who know nearly every trick in the book and approach cautiously, and, ya know, it's a controlled plasma-beam/laser in front of you than a single or double edged blade, the constant reimagings don't hold as much weight than the classic fight. It's all flash, no sustenance, marred because Lucas candied it up for the Prequels, and then Disney sort of turned it down for the Sequels (then gave us fanservice with R1). When Plinkett said 'Yoda should never have a lightsabre', I have to agree.
Kenobi's ancient and besides cutting up ruffians, has had no recent experience. Vader is a middle-manager cyborg in a very poor quality suit. These aren't young whippersnappers - that goes to Luke, and the first time Luke gets into a fight, he gets played with by that middle manager; the second time he has to forgo nearly everything he learned just for brute strength to get Vader down, which was more akin to a young kid just wailing on the milkman who is his real father - for Vader is emotionally compromised at that point. If Vader wasn't, or didn't know that he was Luke's father, and saw him just as a threat to his position, Luke wouldn't had won that fight.
So it doesn't fit right with me, seeing this old desert-burnt hermit and this broken shell of a man suddenly get the energy of teenagers, ya know? Kenobi doesn't have to turn to cut a box, he can just put his saber behind him and amplify it with the force or w/e to cut it Armaggedon style. It's not like it makes any difference vis Vader as he's just as open doing that as he was as open in the reimaging where he turns his whole back to Vader, and so on.