For me, Wally West was a core concept issue.
My problem with Wally was that his origin was always dependent on [his uncle and previous Flash] Barry Allen. He was never his own character. He was always going to be subservient to Barry in some way because his origin was determined by Barry. There was always a Flash in front of him and his powers were because of him.
I always felt, as a true Flash, if we were trying to get to the simplest form with regards to media and things like that, we had to go back to Barry because the story starts with him.
With [original Robin] Dick Grayson — and this is the same with Wally — people loved them because they aged with them, so they feel this affinity that these guys have grown up with them. The problem is that much like Batman and Superman, now Dick Grayson and Wally West have to stop aging, because they're going to pass their mentors.