Ra's only fought Batman.
Beatrix not only killed 99% of the Crazy 88. She fought and killed the worlds best assassins and trained with the best grandmaster in the world.
And highly doubtful Ra's could stand against Shadow. He and Snake Eyes were superhuman and showed far more skill in their fights.
The problem is Nolan made his world far too realistic. So a lot of the fights are slow and plodding. Even when someone is supposed to be highly skilled like Ra's, it's nowhere near as impressive as it could be.