I was listening to Il giuramento, an opera by Mercadante, the top dog among 19th century Italian opera composers whose work hasn’t survived in the repertoire. He writes smooth melodies, whips up at least the appearance of drama, and expertly handles every aspect of the 19th century Italian style.
So what’s missing? I’d put it this way — his characters never grab you, singing (as a subtext to whatever their words are) “I am somebody!” (To borrow Jesse Jackson’s phrase.) Listen, by contrast, to just about any Verdi aria. Verdi’s characters are always somebody, so strongly so that we take it for granted, and imagine (or at least I do) that this is just how Italian opera is.
It’s easy to mistake this for an achievement in musical composition. It isn’t. It’s an achievement of imagination, which composing serves. If you’re blessed (or cursed) with dramatic imagination, you’ll hack away at your music till it sounds like the people you imagine. And you don’t need special composing talent to do that. You’ll do it at whatever level you’ve reached as a composer. Look at Boito — he had modest composing skills, but fabulous imagination. His music isn’t very good, much of the time, but it’s vividly dramatic. (Not that it wouldn’t be more vividly so, if he wrote more vivid music.)