Should be fine to see regexp in Find & Replace dialog.
And maybe fine too: when column artist is selected, or just one field then initial value of field " where search " should be same, not last set value.
Find in selected fields is welcome too 
Find and replace regexp
In the meantime, MP3Tag has support for regex’es.
Im lack ofthis feature in Jaikoz , so i wrote this feature request. Im not interested in mp3tag.