Why such a long training time?On other superhero news: Danny Zabbal's lesser-known superheroes. Below: Insomnia Man, the hero who never sleeps. Also via MeFi.
Batman can't really afford to lose. Losing means death—or at least not being able to be Batman anymore. But another benchmark is having enough skill and experience to defend himself without killing anyone. Because that's part of his credo. It would be much easier to fight somebody if you could incapacitate them with extreme force. Punching somebody in the throat could be a lethal blow. That's pretty easy to do.
But if you're thinking about something that doesn't result in lethal force, that's more tricky. It's really hard for people to get their heads around, I think. To be that good, to not actually lethally injure anyone, requires an extremely high level of skill that would take maybe 15 to 18 years to accumulate.