I'd still say that the best procedure would be to apply the converter filename-filename instead of insisting on an action.
But this has been described exhaustively in
Aktion für Trackumbennenung
(the German thread where you asked the same question).
Using that converter plus the filter
%_filename% HAS ")"
would save you the bother of catering for various amounts of bracket pairs.
But everyone may do as he pleases.