Finesse would definitely be good, because it'd make the TWF Samurai much easier to pull off (don't need to worry about pumping up Strength for to-hit rolls alongside the high Dex for the TWF tree). You could make the capstone ability something like "may use two maneuvres on the turn they draw their weapon" (that's assuming you can't already do that- I know there's a whole array of types- strikes, counters, the buffy ones...).