Charmingly girlish, alarmingly garish

La CalistoCovent Garden, London WC2, until 10 Oct

Cavalleria Rusticana/PagliacciColiseum, London WC2, until 23 Oct

The Barber of SevilleColiseum, London WC2, until 8 Oct

Otello Millennium Centre, Cardiff, until 11 Oct, then touring

Transmogrification, cross-dressing, bestial bickering - the shenanigans of the ancient gods offer a carte-blanche adventure playground to opera directors and designers. Luckily, Francesco Cavalli's score for his 1651 opera La Calisto is exquisite enough to survive anything the fevered imaginations of David Alden and his high-budget visual team choose to chuck at it, from tedious campery to a stellar metamorphosis.

From the moment a bulbous, multi-eyed monster wanders on stage and sits down to read a fanzine, you know you're in for an over-the-top evening of postmodern theomorphics. By the interval, we are wearying of a preening cavalcade of satyrs, centaurs an d transsexual grotesques, flaunting their genitals amid a riot of rumpy-pumpy. Were Mary Whitehouse still with us, the Royal Opera would surely by now have joined the National Theatre on her writ-list.

At the centre of all the designer decadence is the comely, vulnerable normality of young Sally Matthews in the title role, acting and singing her way with beguiling charm through the serial attempts of Umberto Chiummo's witty, well-sung Jove to seduce her. When he disguises himself as her mentor, Diana (Monica Bacelli), complications also ensue for Lawrence Zazzo's ardent Endymion, the hapless rustic besotted with the supposed goddess of chastity. As Jove's long-suffering wife Juno, Véronique Gens hounds hubby with elegant exasperation.

Early on, Ovid's magical fountain becomes Alden's Las Vegas water-cooler. Via stripteasing nymphs and sequined torch singers, he proceeds to mount a series of over-populated set pieces which lose all sense of narrative, confusing the audience thoroughly, before reaching a breathtakingly beautiful climax as Calisto is transformed from a bear into a constellation.

Do reopen your eyes at this moment, if you've sensibly shut them to avoid the garish onstage distractions from the ravishing playing of the Orchestra of the Age of Enlightenment under Ivor Bolton. Complemented by the Monteverdi Continuo Ensemble, and a uniformly immaculate cast, they make Cavalli the true star of the evening, for all Alden's attempts to drown him out.

At English National Opera, the equally radical Richard Jones takes a similarly revisionist approach to the hallowed verismo double bill of Mascagni's Cavalleria Rusticana and Leoncavallo's Pagliacci, joined at the hip since their adjacent premieres in the early 1890s, and collectively known to operamanes as 'Cav and Pag'. His take on the latter is far more successful, recasting the central Canio as 'Kenny', a world-weary 1970s comic touring the English provinces with his TV sitcom sidekicks in a pants-down v audeville farce.

The complex conceit of Jones and his designer Ultz, in Lee Hall's loose English 'adaptation', is to place us outside, then backstage and front of the small urban rep to watch cast and audience simultaneously as the inevitable tragedy unfolds. Kenny's wife Nelly, played and sung with brio by Mary Plazas, is two-timing him with the stylish Mark Stone's stagehand Woody; when he's alerted to this by his sidekick Tony (Christopher Purves on top sleazy form), a very English bedroom romp turns into an Italian revenge bloodbath.

On the posters, Kenny looks like Les Dawson; in Geraint Dodd's understated portrayal, he seems to start as Harry Secombe, then dwindle into every comic on the verge of suicide. With Edward Gardner wringing real romantic agony from his fine house orchestra, this is the kind of witty operatic update that makes perfect dramatic sense.

Less so 'Cav', for all Gardner's impassioned musical leadership. A traditional enough version of this other blood-stained, revenge-fuelled love triangle, in an arch translation by Sean O'Brien, is fast-forwarded to a 1940s village hall, which uneasily houses the Easter Mass as well as covert adultery and unruly town meetings. The stage box lends the proceedings an apt sense of claustrophobia, but cramps the style of an excellent cast led by the commanding Jane Dutton and Peter Auty, as rich a lyric tenor as Britain has produced in decades.

One last curtain call after the interval, before the first of many set changes during Tony's prologue to 'Pag', wittily suggests that Kenny and his crew have also been responsible for 'Cav'. The in-your-face bravura of Jones's double bill gets ENO's new season off to a promisingly populist start, bolstered by the umpteenth revival of Jonathan Miller's hilarious 1971 staging of The Barber of Seville with its best ensemble cast yet. Anna Grevelius's fiery Rosina and John Tessier's ardent Almaviva are exciting new arrivals, even if Garry Magee seems somewhat out of sorts as Figaro; but the show still belongs to Andrew Shore's blustering Bartolo, a role he has made his own. Another plus is Rory Macdonald's brisk, finely detailed conducting.

In Wales, by contrast, trad is back. The Scottish director Paul Curran, better known around Europe than in his native isle, has opted for grand-scale, Cecil B DeMille magnificence in his new staging of Verdi's Otello, so steeped in Renaissance splendour as to seem like a framed, inanimate portrait of Shakespeare's play set to music by his Italian admirer.

The opening tableau highlights the flowing blonde locks and risque frocks of the ageing warrior's young trophy wife, Desdemona, sung clearly but coldly by Amanda Roocroft, thus eliciting little of the sympathy due the victim of David Kempster's devilish Iago. Kempster towers over Roocroft and Dennis O'Neill's Otello not just physically but vocally, to the point where he challenges the outstanding WNO chorus and Carlo Rizzi's polished conducting for the evening's laurels. At 60, O'Neill still sings with sufficient authority to merit this sumptuous showcase; for all his stage assurance, however, he lacks the heft that is the sine qua non of this particular tragic hero's fall. It is indeed a rare Otello that entirely fails to move.