Downloading discographies (or any other file) that have different naming patterns is a hassle and things only get worse have your own organization.
My request is that when the user has selected multiple files and presses F2, a simple textbox shows up, in which every line represents a file.
If by any chance you ever used Everything's Multiple rename feature, that's very similar:
No need for RegEx support since, I assume, the majority of users that would need this feature already have an external text editor with such capabilities. You'd just copy the file list, edit it externally, then paste it back, Tixati renames the files and the user can keep on seeding.