Yeah, I don't agree.
Pretty much all of Diaby's performances (such as he's had) in the last two or three seasons he's shown fairly mature use of the ball—high pass completion etc—and a lot more discipline getting back to cover the defence than he originally had.
He could never sit in front of the defence for toffee, but he did eventually develop a much better radar for when Song or another midfielder sharing that responsibility was getting forward.
Denilson actually possesses most of the faults—limited passing vision, low foot speed and laziness—that the other two are often accused of having.