Then again, I now recall that it was Peter Sellars who directed the Golijov piece, as well as the presentation of Mozart's (unfinished) Zaïde seen last Friday. But he and Golijov are a natural couple. Mozart, not so much.
The most obvious thing about the Zaide fragment is that it's, well, fragmentary. The piece lacks an ending, but more jarring in performance is the absence of any dialog linking the numbers of this singspiel. Sellars adds no dialog -- skeletal, updated, or otherwise, though he does interpolate a few numbers from another Mozart fragment (Thanos, King of Egypt). Instead he has the performers crudely pantomime in the grossest stereotypes: Gomatz as prison bitch, Osmin as a fried-chicken-eating hood, Allazim as the magic negro, and Zaide herself as a submissive-then-shrill Chinatown FOB (her actual costume being rather more loaded than that shown in the PlaybillArts link above). These latter depictions crossed, I think, the line into racism, but perhaps more offensive was how insultingly stupid they all were in light of Mozart's musical characterizations. Only Soliman was allowed some variety of poses -- none subtle.
These were intentional choices, and show Sellars and Mozart working at cross purposes. Sellars, as with the Golijov piece, tries to heighten the populist sense of the piece by flattening out individual aspects of the characters, leaving them more symbols of oppression and victimization. So Gomatz, with nothing to say, has no personality and is merely (and purely) pathetic; while Zaide herself -- whose music threatens to open spaces of expressive and human variety -- is otherwise straitjacketed in strict stereotype.
Now it's true that Mozart's form for Zaide -- a vernacular rescue opera employing not comedy but (at times) melodrama -- invites a certain amount of popularizing and cartoon-izing. (One sees it even in Fidelio, in the mustache-twirling aspect of Pizarro that's difficult to take seriously.) But nothing in Mozart is as inhumanly didactic as Sellars would make this piece; the personal and individual foibles of the suffering always get space. (And perhaps he abandoned Zaide for its inflexibility on this point. The comic angle of the later Entführung provides more possibilities.)
I regret, in part, compounding the Mostly Mozart Festival's error in headlining Sellars' contribution to the show. That he made himself the story with a harmful staging was part of the evening, but could hardly be the whole in a Mozart evening. But the musical haul was itself mixed. Festival music director Louis Langrée led the period group Concerto Köln in a viscerally exciting account of both Zaide and the Thanos excerpts. This seemed to play to their strengths as an ensemble, while being of a piece with the popularizing tone of the production. But excitement worked against tenor Russell Thomas (the Soliman -- whom, incidentally, the Sun's Fred Kirshnit misidentified as a bass-baritone): usually precise as well as fascinatingly intense, he'd apparently been encouraged to sacrifice much of the former for a bit more of the latter. Still, I hope to hear him in more leads soon. The best singer on the night was bass-baritone Alfred Walker (as Allazim), whose rich dark tone was the event's main pleasure. The others, unfortunately, made little vocal impression.
Is Zaide an overlooked masterpiece? It's hard to say. The piece is best known for Zaide's arias, but Korean/American soprano Hyunah Yu (the only non-black singer in the cast, by bizarre intention) didn't -- or wasn't allowed to -- make much of them. As for the rest, the lack of dialog threw off the pacing of the work as a whole, which actually seemed much longer than it would have with some intervening talk. And I admit being unable to ignore a particularly bad or offensive staging. So -- ask me again, after a better-realized concert version.
The veneer of contemporary commentary is too silly and tiresome to discuss. But it -- as laid out at length in synopsis and program notes -- shows that Sellars would've had no problem adding dialog, if he'd so chosen.