While BRU is a great tool, it is unfortunately almost impossible to use for nontechnical users. Please, no flamewars about "My grandmother can use it so there!", try sitting an average, non-geek user down in front of it and see how long it takes them to rename their holiday photos from DSCnnnn.JPG to "My holiday pictures mmm.jpg", where nnnn are the arbitrary camera-assigned numbers and mmm is a more obvious sequence 1, 2, 3, ...
It would be nice if BRU provided a simplified mode for non-technical users that just wanted to rename their holiday pix or some similar task. Putting on my UI design hat, what you'd do is simplify the file window to display only the "Name" and "New name" columns, along with a text box to enter the new name pattern, which automatically gets a counter value appended to it to create unique names. In other words if the user selects a collection of (say) photos DSCabcd.JPG and enters "Holiday photos" in the text box, they'd get renamed to "Holiday photos 1.jpg", "Holiday photos 2.jpg", ...
So the sequence is: Replace the name with the user text, add a counter if there's more than one file, and lowercase the extension (since things like photos typically come from FAT-formatted media).
Functionally it's pretty primitive, but it'd satisfy the needs of many nontechnical users without intimidating them with the current user interface.