I would like to suggest to be added loading/progress bar in some steps.
Some steps that I notice are very confusing to clients is when they click on the image to add to the upload zone, sometimes it takes a few seconds and they don't give enough time to it. there should be some way to block the screen with progress bar, or loading icon.
Added in V4.6.8
it is difficult to undestand on the video because you can't see when I click the picture but it takes a while to place the image on the upload area. The client usually clicks several times and the site crashes
It only happens on mobile.
On desktop it show a loading icon
Could you do a screencast and post it here what you mean exactly!