Les Troyens is one of music's mythical beasts. The greatest opera that few will have ever seen. Until recently the epic was considered so demanding that it was thought unstageable. David McVicar's new production for the Royal Opera House is only the second in its history. So for most of us last night will have been the first chance to witness the five-hour masterpiece in its original French. 

It is amid the murmuring woodwinds that the most memorable musical truth of Troyens is to be found

 According to Oscar Wilde’s Salome (and faithfully preserved in Hedwig Lachmann’s libretto), the mystery of love is greater than the mystery of death. That may be so, but neither comes close to equalling the baffling mystery that is still David McVicar’s production. Not trusting the simple reds, moons and veils of Wilde’s stylised original to conjure sufficient horror, McVicar takes his abused heroine to Nazi Germany by way of Pasolini and a backstory of physical and psychological trauma. Then he throws in an abattoir and plenty of blood.

There’s a glamorous grubbiness to John Copley’s returning La Bohème that makes Puccini’s bawdy and romantic romp through the under-lit alleys of Paris’s Latin Quarter especially enjoyable. Beyond the beautifully mournful portrayal of the tortured artist and his suffocating love, there’s something devilishly attractive about it all. If anything, Copley’s direction (he is tonight celebrating 50 years since first directing at the ROH) could do with more grime under its fingernails, or a harsher and less pretty winter to really make his characters suffer in the opening acts.

Since it obviously can't be taken in any way seriously, one big plus for Donizetti’s deeply silly (and, narratively, extremely sketchy) operetta is that it offers everyone plenty of room for manoeuvre(s), an opportunity the Covent Garden team had clearly decided they were not about to miss when putting together this twice-revived production.

A director who is “passionate about biology”; a humorist who “hardly ever mocks”; an artist who speaks fluently about the origin of species; a non-musician who has directed some of the best-received opera productions of the modern era; a doctor with his own profile on IMDB. In short, a man who puts the “poly” into “polymath” – and like as not does it in Greek. Don’t you just hate Jonathan Miller?

David McVicar’s Rigoletto hurls full-frontal nudity and an orgy at the audience within its opening minutes – dramatic grenades to clear the well-worn ground ahead. Back in 2001 this may have been enough to shock-and-awe, but a decade and a couple of revivals on and it takes rather more. And more we certainly get in the current revival. Not only does Italian superstar tenor Vittorio Grigolo take his turn in the Duke’s tight britches, but John Eliot Gardiner takes charge in the pit for this, his first Rigoletto.

New Royal Opera director Kasper Holten has announced a 2012-13 season in which big-name favourite operas and world opera stars are threaded through by 19th-century rarities and British operas. ROH music director Sir Antonio Pappano conducts a deliberate series of revivals, including Verdi masterpieces and four complete Ring cycles.

I find it hard to square what I know about composer Judith Weir with what happened last night. In one corner lies her 30-year output of songs, choral pieces and operas - as engaging and beguiling an oeuvre as that of any living composer's. I think of her waggish song cycle King Harald's Saga or her playful opera A Night at the Chinese Opera.

When blithe Susanna and not the expected Cherubino emerges from hiding before the astonished Countess and enraged Count, the latter instantly back-pedals on the fury he has been heaping upon his seemingly faithless wife. She rounds on him: “Crudele, più quella non sono!” (“Traitor, I am no longer her”) and everything suddenly stops. It's a tiny two-beat rest that usually goes for nothing except the signal for a key change, but here the moment is charged with drama. The Count shoots apologetic looks to cover his shame and the Countess painfully registers her lost trust.