Changes to endings in adaptions are nothing new, unfortunately. Most of the time, they make absolutely no sense, but there is the rare occasion when it does.
In Gluck's opera version of the Orpheus and Eurydice myth (Orfeo), instead of Eurydice being sent back into Hades after being looked upon by Orpheus, Cupid comes to the rescue, saves Eurydice, and brings her back to the normal world. It's completely bizarre, especially after an entire depressing, melodramatic, 90 minute opera. It's totally pandering to the audience. I'm hoping that we're not getting the same deal here with Porgy and Bess. Still very anxious to see it.
-There's the muddle in the middle. There's the puddle where the poodle did the piddle."