Why is the Samurai class considered taboo in non-Eastern settings? [...]
Discuss (but please be civil ;-) )
Let me turn the question around. What do you get from a samurai that you don't get from a cavalier?
If someone said to me "I don't want to play a wizard, I want to play a thaumaturge," my first question would be "what's the difference?" Ditto if someone said "I want to play a lama, not a cleric" or "I want to play a scoundrel, not a rogue."
In my experience, the Eastern flavor (and the katana) are what motivates most samurai fans. If you reskin by taking those away, you've eliminated the motivation for the player. But those are also what most GMs object to. If flavor is the only thing the player is after, but also what the GM objects to, it's hard to find a common ground.
Resolve. I love the idea that I can shrug off a magic assault that would otherwise have affected me just because of sheer heroic willpower.