I haven't tested myself, I'm on PS3, but here are the reported findings from 360 players.
His regular knife hasn't change, the recovery is better on his ex knife.
he can have both, a regular and an ex knife on screen at the same time, and ex knife can be done in juggles followed by a ball.
jiP, b+1,1,2 dash 2,1,2 dash 1 ex knife ball- 40%
His juggles are also easier on his 2,1,2 very realiable now to connect after b+1,1,2. also 2,1,2 doesn't drop anymore more after another the first 2,1,2 or f+3, b+2.