In the Export Existing Files box add 'Ask' option so you don't have to pre-define -add suffix -overwrite or -skip with every export.

What problem do you see this solving?

When exporting files sometimes I want to 'overwrite' and other times 'skip' or 'add suffix' to files with the same name in that folder. Usually I need to overwrite, but by keeping this setting checked, I may accidentally overwrite files in the future that should have been skipped or saved with a different suffix.

A better solution would be to add an option called 'ASK' which would open a dialog box if you try to generate a file with the same name as one already in the destination folder. In this scenario you could then choose whether to overwrite, skip or re-name. This would be similar behaviour to Lightroom or Windows Explorer for example. This way the export recipe can be much more versatile and the 'existing files' choice can be effectively unlinked from the process recipe.

When was the last time you were affected by this lack of functionality, or specific tool?

Almost every time I export files, I have to be very careful to check which option is selected. Much easier would be a warning & choice if you try to overwrite files of the same name. None of the options are suitable to leave selected all the time, and given these are process recipe's, the whole point is that they should be usable in any scenario without needing to be changed. It would be impractical to double or triple the number of recipe's simply to have one for 'overwrite' and another for 'skip' for example.