There are always many things “wrong” (in your case it’s mostly your specific use case and the place you are coming from, basically mostly your own preferences and biases?) with something, always, always, it’s impossible to avoid. Can’t design for everyone, just can’t.

PS: Check the menu. It’s absolutely crucial for OS X software. It’s a design paradigm Apple has been unflinchingly following forever, with iPhoto, with Aperture, with everything. They will hide all the custom stuff and little features there that depends on subjective preference there. For example, check View, then Meta Data to get your hearts on the thumbnails.

(Deactivate My Photo Stream. It’s deprecated and Apple will hopefully mothball it soon. I agree, it’s confusing, but that’s the debt you acquire when unthinkingly doing stuff. I agree that sucks, definitely. The All Photos album is also confusing, I agree. Apple should have abolished it and had, but people were whining about it. Basically, the Photos view has all your photos in chronological order, the All Photos album has all of your photos in the order you imported them. Also, don’t you have to explicitly share photos for them to be shared? Which is exactly what you want? I’m not sure what your multi-select point is all about. You obviously cannot multi-select when Photos just shows an overview. I agree that’s a tradeoff, but in my view one that’s very well worth it.)

In summary: Photos is modern, blazingly fast, cruft free and extremely logical. I love it. So much better than iPhoto ever was.