I don't think it's a knock on Fish as much as it may be on ARob. I wonder if he's trying to do too much when Fish is healthy in order to earn playing time. It's the same idea as a hitter in baseball "squeezing the bat to hard" and not getting results.
I've noticed the same thing you noticed and it just seems to me that in the NIT run and last night he seems way more relaxed than any other times. He's not thinking and over-thinking; he's just playing, reacting to what the defense gives, and relying on instinct. Maybe the 7ish games without Fish is too small a sample size to make such an assertion, but it just seems like ARob is a different player when Fish isn't in the lineup and I wonder if that's why.
Fisher and Robinson both handle the ball a lot. It seems when both are out there, whoever has the ball is not quite sure what to do sometimes. During the NIT run and last night, roles seemed to be well defined. ARob runs the offense, Vlad and Hamdy sets screens and post up, and the rest spot up on the perimeter.