Something old. Something new. Loved Tyne Daly. Rest is goo. That's all you need to know about 'It Shoulda Been You,' a slight musical comedy about a wacky wedding that's small in size but big in cliches...Fortunately, David Hyde Pierce, in his Broadway debut as a director, cast the show with a couple of one-of-a-kind stars who help make up for their run-of-the-mill characters...The script by Brian Hargrove, a sitcom writer married to Pierce, serves some tart zingers. But his lyrics, written with no fewer than five others, are ho-hum. Music by Barbara Anselmi, who conceived the show, is pleasant lite pop. Most songs just express passing thoughts and are vaporous...In the end, the show is a harmless diversion. But this is Broadway. 'It Shoulda Been You' shoulda been better.