I mean, really, what is the point of Rossini? That’s actually not as stupid as it sounds. No-one has ever mistaken any of his operas for taut music-drama, and even the best of them are peculiarly difficult to pull off because without first-rate singers, everything collapses. That is, without doubt, not a problem facing the Royal Opera’s new La donna del lago. Trust me: London hasn’t heard such spectacular Rossini singing in decades.

An operatic truism still doing the rounds declares that for Verdi's Il trovatore you need four of the greatest singers in the world. For Don Carlo, his biggest opus in every way, you need six. Nicholas Hytner's Covent Garden staging hits the mark third time around with five, the exception being a very honourable replacement for what would have been an interesting piece of casting.

It’s hard to put one’s finger on why George Benjamin’s new opera doesn’t work. It comes to Covent Garden with a wind in its sails. Its outings in Europe have all received high praise. It boasts a classy cast, Martin Crimp as librettist and Benjamin at the helm of the orchestra. The story is a captivatingly horrific medieval morality tale that often goes by the title of "the Eaten Heart story". And there’s little wrong with Katie Mitchell’s production.

Flesh-tearing, woman-raping, body-goring brute he may be, but he's misunderstood, that Minotaur. It's a bold argument to make, but this is the contention of Harrison Birtwistle and David Harsent's 2008 opera. They are aided by a surprisingly cuddly performance from John Tomlinson.

Rolando Villazón at 40 is back on reasonably stylish form, as far as the voice will allow him to go – which is not always up and volume-wise only just as far as the Covent Garden Balcony. John Copley’s Royal Opera Bohème is two years younger than the Mexican tenor. It burns less warmly than the faltering stove in the first act, casts a pall over collective attempts to reanimate the naturalism which is all there in Puccini’s perfect score, and needs a second interval to drag its weary bones back up the stairs to the students’ attic in Act Four.

Few singers provoke more debate than Rolando Villazón. His off-piste projects - from his Romantic exploration of the Baroque to his spell as a talent contest judge - have been much discussed over the years. By comparison, there's something strangely calm and conventional about Villazón's two latest projects: a new album of Verdi on Deutsche Grammophon and a performance of John Copley's La Bohème at the Royal Opera House. Yet you'd be foolish to ignore either.

My phone's predictive text posed an interesting question. Robert le Doable it insisted on calling last night's opera. And it's often been asked of this and other grands opéras. Are they doable? Such was the munificence of the times in which they thrived, and such has been the collapse in their popularity, are grands opéras worthy of resurrection? And do we have the resources and good will to do justice to their singular vision? If any opera company could meet the all-singing, all-dancing demands, it is the Royal Opera House.

You can tell a lot about a performance of L’elisir d’amore from the two pizzicato string chords that so neatly take the sheen off the military pomp of the opening phrase. Played well, these subversive little asides can throb with all the wit and cheeky self-mockery that elevates this opera above the hundreds of Donizetti also-rans. Played earnestly, as they were last night however, they heralded a rather limp performance – laboriously correct without ever finding (let alone seizing) that anarchic glee that riots through the score.

Tonight the Royal Ballet's live Swan Lake opens the most extensive season yet of live screenings to cinemas worldwide of the Royal Opera House's productions. Zenaida Yanowsky and Nehemiah Kish, in the leading roles of the Swan Queen and her evil counterpart Odile, and Prince Siegfried, will be beamed across oceans to cinema-goers in St Julians, Malta, to the Montevideo Moviecenter in Uruguay, as well as to the Apollo, Burnley and the Enfield Cineworld.

Last night's concert performance of Berlioz's Les Troyens was not a Prom for the fainthearted. After all, if sitting through a five-hour opera had been a daunting undertaking for the Covent Garden audiences last month - who could also enjoy David McVicar's eye-catching staging - then it was inevitable that anyone seated in the Royal Albert Hall for the visually pared-down version was expecting to feel very culturally virtuous by the end of the night.