You have a complex renaming: first swap extension and name then make names equally long then sort by number then  renumber then swap extension back then sort by name and add a running number. Maybe this could be done in one turn, but who wants to type it over and over again?

 You want to use a function twice, but with different parameters. Example 1: First replace "a" to "b" and then "y" to "z". Example 2: First replace occurence 4, then occurence 18. You can't do it at once, you would have to rename twice.

 You have a folder where new files are added and as soon they're added, they should be renamed. For example add leading zeros to existing numbers.

 You want to rename files later, because now it's not possible, e.g. because the files are on a CD.

I plan to be able to accumulate multiple filename changes like a queue.

This function is kind of a sister to save settings. I plan to implement save settings, so maybe save renamings=macros isn't far away.

This function is a brother of command line options, because you could save a macro and then run that macro on start up. I will see what I can do.