To use user-friendly fieldnames is really helpful for the users. I suggest to use a reame fields using MapTab; approach which could ensure that the fieldnames in the application are always the same even if they change in a previous process-step (the MapTab of course must be also adjusted if there are changes).
We received an answer from someone at Qlik that we talked to. He showed us how Qlik Sense (and QlikView he said) are smart enough to handle renames without breaking existing visualizations. If you use an AS in a load statement to rename a field, Sense keeps track of what the original source field was. If you later rename the field in the load script while the source field remains the same, Sense knows it is the same field. Any visualizations linked to the old name are updated to the new name so that nothing breaks.
We actually have a program that dynamically generates the load script, so changing the load script to reflect the user configured value works for us.
If we had a static load script, using rename fields using map would be worth investigating. As long as the rename fields command tracks name changes the same way the AS keyword does, it should work. Since the AS will meet our needs, however, that's the solution we're going with.