Originally posted by The_Jonas
It's more catching than vision.
It's a combination of the two, but I find that catching has less focus as an attribute, contributing to more widespread uses with more disparity, while vision has a large amount of its benefit coming in the way of smoothly catching in stride. As well, I have seen receivers with third-capped catching who still stutter step when they catch. By the time vision is paid some attention, at least with minor attribute focus, the issue is almost entirely resolved.
However, I'm also sure that you can overcome stutter-stepping by simply having a better catching score, being in a better position on the ball, and by having better pass quality.