As you can see from the Holly post, I was able to get the "Photos" app working today, despite my gretzing, and all by myself. I decided to take the plunge so I picked a photo library at random and got lucky — all my photos were in it. They loaded correctly and are usable again.
But as I expected, Photos is not as easy to use as the old iPhotos app was; I'm missing it already. It's annoying! For example, I can't see my photos' ID numbers, and I often need those when I'm selecting photos to import from a large group. Editing is sloooowwww and not as simple as in iPhoto. And every time I open the app, all the photos look horribly blurry and take an eternity to sharpen up. It may be that my aging laptop can't handle the upgrade.
I know I'll get used to it. I have to: it's the way of the world. Software developers need to keep getting paid. They start by making a great product that becomes popular. And then they keep mucking with it and releasing new, more complex (and often worse) updates... to keep getting paid. Then they realize they've got a crappy product that no one wants anymore. So they develop and release a shiny new product, which starts out decently, and then gets mucked up over time, too. They keep their jobs because they've always got plenty to do. It's a rule of the digital universe: everything eventually gets worse, especially if it was perfect to begin with. If you like the way an app, website, or piece of hardware works, enjoy it while it lasts — because it won't stay great for long.