When Purcell died at just 36, he left The Indian Queen unfinished, which only adds to the usual problems of staging his "semi-operas" – plays with musical interludes which don’t really accord with modern operatic tastes, despite the ravishing beauty of the music itself.

After 16 years one might expect a revival of a repertory opera like Hansel and Gretel to come up with a dusty look and frayed edges. But Benjamin Davis has done a brilliant job pumping the life back into Richard Jones’s memorable but intricate 1998 staging of Humperdinck’s pocket Wagnerian masterpiece.

Farinelli and The King is pretty much a perfect piece of theatre. More importantly, though, it’s perfectly timed. In a month when English National Opera’s troubles have made the front page, when op-eds are all about why Simon Rattle’s dreams of a new concert hall for London are fruitless, this paean to music – to its serious, healing, transformative power – is not only resonant, but necessary.

The good news first: director Christopher Alden’s new production of Gianni Schicchi is quite brilliant, and one of the funniest, cleverest things you’ll see in an opera house. Puccini’s taut one-acter is difficult to mess up, but it takes some skill to present it this well. Alden’s version is full of pleasures. Like Rhys Gannon’s stroppy young Gheradino, who spends most of the action wearing headphones and playing on an iPad. Choreographer Tim Claydon’s mute, acrobatic Buoso Donati leaves this earth with some reluctance, his ghost continuing to haunt the stage.

After seven glorious Welsh National Opera performances in the summer of 2010, it looked like curtains for Richard Jones’s Mastersingers (or Meistersinger, as it then was, sung in German): no DVD, no co-productions. The director seemed happy with that, as philosophical as Wagner's operatic characterisation of 16th-century cobbler-mastersinger Hans Sachs. Such, he implied, was the ephemeral nature of the true theatrical experience, rare at a time when nearly everything gets documented.

Like the Dutchman himself, Tim Albery’s Der fliegende Holländer makes its inevitable return to the Royal Opera House. Unlike the Dutchman, however, this production has broken free of its cycle of repetition. Perhaps expectations have changed, perhaps after two outings I’ve just surrendered to Tim Albery’s severe and sober staging, but for the first time since its 2009 debut this ghostly ship finally comes in to emotional harbour.

To pair Rachmaninov’s brooding and little-performed The Miserly Knight with Wagner's brooding but much-performed Das Rheingold is an audacious piece of programming. The operas share an interest in the mortal power of money, and Rachmaninov’s score has a more distinctly Wagnerian colour than much of his later work. To do so in a single evening, requiring substantial cuts to the score of Rheingold, and to stage them in the Royal Festival Hall, shows boldness verging on the reckless.

What kind of regime, asks Gérard, talks of justice while killing poets? It’s a question the answer to which suggests itself all too swiftly this week, briefly turning a revolutionary romp of an opera into something rather more chilling. Playing things straight in his new production of Andrea Chénier (if wigs and lavender stockings, chandeliers and pastoral divertissements can be called straight), David McVicar may have missed a trick with a story that speaks with surprising clarity about the violence of political and ideological conflict. Or maybe he didn’t.

It’s quite a distance from the first performance of Monteverdi’s operatic cornucopia under the Mantuan Gonzagas’ imperious eye to this democratic celebration at the Roundhouse – 408 years, to be precise. Michael Boyd’s production takes us back even further, to those ancient Greek festivals of poetry and music which inspired the intellectual Florentines to fashion the art of opera in the late 16^th century.

When everything works – conducting, singing, production, costumes, sets, lighting, choreography where relevant – then there’s nothing like the art of opera. But how often does that happen? In my experience, very seldom, but not this year. It's been of such a vintage that I couldn’t possibly choose the best out of six fully-staged productions – three of them from our only native director of genius, Richard Jones, who as one of his favourite singers, Susan Bullock, put it to me, deserves every gong going – and one concert performance.