From the developer's point of view, I can appreciate it's not a friendly or easy to understand syntax. But I'd still love it.

For the matching of conditions I would imagine it could fit in more easily, perhaps in the drop down "starts with" there could be a "matches expression" or something... I dunno.
Just throwing the idea out there as I didn't see it anywhere else... I guess in the meantime I can look at writing a shell script for the renaming side. I've not started to play with that yet, though.