Carousel, Savoy Theatre, LondonSchool of Dance, Barbican, London

Is that a hornpipe – or are you just pleased to see me?

You're a queer one, Julie Jordan", sings the best friend of the heroine in Richard Rodgers' and Oscar Hammerstein's Carousel. But it's this 1945 musical that's really queer. It's almost a lesson in how not to construct a musical.

Only 15 minutes in, the leads have already delivered the show's one big plush love ballad: "If I Loved You", even though they've only just met. The hero dies halfway through. Perilously near the end a new character is introduced, by way of a 10-minute ballet. And rather than bring the curtain down on a rousing hoedown, as the same authors did with Oklahoma!, they end the show with a hymn. It's not Richard Rodgers' fault that "You'll Never Walk Alone" was hijacked by Liverpool FC, but it adds to the sense of dislocation.

That said, Lindsay Posner's production does a remarkable job in smoothing the work's oddnesses. Unlike the Carousel mounted by the National in 1992, it doesn't probe for darkness so much as shine a compassionate light on its themes: how lack of self-respect breeds domestic violence; how personal failure risks becoming a family legacy; how a stout heart and good friends can pull you through.

Some material is strikingly out of kilter with 21st-century mores. The battered Julie refuses to condemn Billy's violence "'cos he's your fella, and that's all there is to say". And it's only the calm force of Alexandra Silber's acting, the integrity of her singing and quiet, almost spiritual presence that could persuade us to view this as a legitimate position. Tall as a reed, mellifluous of voice, not pretty, but facially mesmerising, newcomer Silber is the moral hub of this unmerry-go-round. You hang on her smallest responses.

Another curiosity of the original musical is the way the dance is distributed: a wodge in the first half, then nothing till the end. Adam Cooper's choreography is admirable in the way it slips organically in and out of the action, echoing visual themes of William Dudley's set. On the New England shoreline, with the masts of fishing vessels drifting by, the girls from Nettie Fowler's spa kick their legs high so that their skirts flare like sails. The trawlermens' hornpipe is so ruggedly muscular that it almost bursts the confines of the Savoy's stage.

As Nettie, Lesley Garrett is bizarre casting, notwithstanding her box-office pull. Radio mikes and operatic voices are rarely happy partners, and the sheer volume of Garrett's top notes makes you want to cover your ears (your eyes, too, when she waggles her breasts in an explosive "June is Bustin' Out All Over" – the words "virginia creeper" have rarely sounded so dirty).

The dream-ballet in the show's final stretch is a major test of the choreographer's narrative skill. It must introduce Louise, the teenage daughter Billy Bigelow didn't live to see, give a thumbnail personality sketch and show why she risks falling into the same underachieving rut as her dad. Cooper clearly draws on his own memories in the marathon he devises for Lindsey Wise – the language is part Ashton's Isadora Duncan, part Matthew Bourne's swan – but it delivers terrific verve and style.

And lastly ... it was only a matter of time before someone dreamt up a droll riposte to Strictly. The Barbican has got there first with School of Dance, a fun 70 minutes which dresses up a beginner-level class in rumba, cha cha or samba (you choose) with a cod history lecture and comically OTT demo by Miss High Leg Kick and Boogaloo Stu, resplendent in dayglo wigs.

'Carousel': (0870 164 8787). 'School of Dance': (0845 120 7550) to 20 Dec