Re: What didn't you like about the film?
^ I am sure they could have added the samurai training aspect by reducing some of the unnessary stuff. For example, did we really need Harada? What was the purpose of that character?
Logan would still have been at his lowest, making the martial arts training difficult, but it would have been able to help him move on. He wouldn't have started as a "badass martial artist". It would have actually been funny to see the master beat Wolverine's rage with unparralled skill. This would have added a whole new dimension to on-screen Wolvie.
I guess what I'm saying is that all of your reasons to not include this don't hold water since you could have still done everything you bring up, which might of actually have been enhanced with Wolvie being trained as a Samurai!
This was a lost opportunity for Wolverine's on-screen character and it wouldn't have been a diversion if it was incorporated into the story properly!