That leg armor is so Dark Soul-ish <3 I'm in love with that.
Also, how neat would it be if this skin had a toggle for the visor of the helm?
Going on, I really like the skin concept, the color choices, and the overall impact (the plume in place of the hair was indeed a clever solution), and there is one small suggestion I'd like to make.
For his sword, have you thought replacing the longsword with a falchion or a scimitar?
The fact is, longswords don't really fit with Yasuo style of slashing since, as you probably know, most longswords were bastard blades, which means they were sharp on both sides of the weapon.
Yasuo handles his weapon that way because his weapon has only a sharp side , and thus he have to rotate and slash.
On the other hand, falchions and scimitars have only 1 sharp edge , while being western style enough to fit with the knight theme.
Examples:
http://www.wulflund.com/img/goods/en/medium/falchion_combat_battle_ready_czech_b.jpg
http://www.strongblade.com/prod/prodimages/sbj-bonedancer1_m.jpg