"New Vivaldi work heard for first time in 250 years"... I don't want to sound snippy or anything, but are we sure they didn't just take one of Vivaldi's identical-sounding pieces and give it a new title?
Okay, that did sound snippy. And it's unfair, because a lot of Vivaldi's reputation for writing pieces that all sounded the same derives from the years when they were mostly all played the same; the advent of "historically informed" performance (which came about in part because people like Nikolaus Harnoncourt wondered why once-innovative composers like Vivaldi sounded so boring when played by modern orchestras) has opened up more of the different possibilities and different sounds in his concertos and choral works.
Still, as a small-p philistine, I do kind of find it hard to tell one piece by Vivaldi from another, just as, according to the article, experts apparently found it hard to tell Vivaldi from Galuppi.
And too much Italian baroque music puts me in mind of that Peter Schickele sketch where a classical music station challenges "I Virtuosi Di Hoople" to identify different pieces by a baroque composer named Arcangelo Spumoni -- each of which is the same melody in a slightly different arrangement. The routine ends with a line that could be the baroque fan's mantra: "The winners will receive the complete works of Vivaldi, which will be sent out to you one record a month for a period of 35 years... and for the losers, we have a consolation prize, the Toscanini recordings of the nine Beethoven symphonies."