I don’t even mean more variety in assets, don’t get me wrong, just something to add additional feedback when you move.
Imagine that you’re playing with audio muted and have a long straight corridor in front of you. In perfect crawler you have some visual feedback for each step, like different floor, ceiling or wall art with even minimal variations, like scratches, dirt spots or discoloration of any sort. It should benefit any instant-step movement crawler as you’ll get a visual feedback on each step. And it can be placed appropriately to the view distance, so you can keep track of your movement by looking at “that wall with a dark spot on it” or “floor with some scratches”.