Do (scientific) editors complain with the publishers about user experience?
Of course we do! I don't edit for any of the big commercial publishers, but I do for top open access publishers that use similar or even the same manuscript submission systems. I'm continually badgering them about this detail or that one. 

Some get fixed, some don't. When they don't, I'm not really sure why not. Maybe the systems don't allow the flexibility. Maybe there are good reasons for the hassles they impose. Maybe the journal staff are so busy putting out bigger fires that this never makes it to the top of the list.