Kurosawa is no question, THE great film director. Nobody else maintained that kind of level of quality over that many movies.
That said, Ran for me was a bit of a disappointment last time I watched it. I saw it in the theatre when it first came out and felt like a 2x4 had just clopped me over the head. I was utterly devastated by the film. But seeing it recently, I felt that it pretty much fell apart after the big battle at the castle. The final third of the film just didn't have much tension to move it along.
On a semi-related note:
The guy who taught me swordsmanship is the guy who taught Toshiro Mifune. Sugino Yoshio -- his name appears in the credits to Seven Samura as swordfight choreographer. He died a few years ago, but I surely do consider myself blessed to have had such a teacher.
And yes, Mifune was having real arrows fired at him. Apparently he hated it, so Kurosawa did it to him in every movie. By the time I saw studying at the dojo, Mifune had grown too senile to make public appearances but apparently he'd continued coming to the dojo long after he'd stopped playing samurai. And apparently he was just as cool in real life.