Just a few thoughts on the design here...I love it, but I have a few small problems with it.
I see arrows, and no bow. So unless he's planning on throwing them like giant lawn darts, they're not serving much purpose.
No problems with the hood, it's classic AC and shouldn't be changed. I think that I'd like to see a mask underneath it, though, or at least part of a face, not just a big black hole. He's an assassin, not a ghost, and adding one of the demonic half-masks that samurai wore to increase their threat would fit in nicely with the armor he's wearing.
Third and last: his hidden blades. They might fit better with the rest of the character's appearance if they were in the Japanese style, with single-edged blades and tanto or leaf-points rather than the double-edged dagger-style blades of the more western assassins. The hidden blade's design has had a few changes over the series, so I'm fairly certain that rendering these more as tanto's would have have been fairly lore-friendly.
Regardless, it's still an awesome-looking picture. He looks like a badass, as well he should, and even with the problems I have with it, I still love it.