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.

I actually like the photostream. It's an easy way of getting recent phone snapshots onto my computer for exporting or doing whatever I want -- without keeping them around forever.

My multi-select comment refers to this: double-click on a photo in the thumbnails. You're now viewing an enlarged photo. Now there's also a double-row of thumbnails to the left of it. You can use this double-row to navigate, but not to multi-select. You must hit the back arrow to get to the OTHER thumbnail view in order to multi-select. I constantly make this mistake, it's so non-intuitive that you can't multi-select thumbnails to (say) export multiple photos.. not in THIS mode, at least, you now have to hit a back arrow to do the exact same task!

I'm not sure if they've fixed this in Photos, but a big gripe of mine with iPhoto was its "sharing" behavior. If you deleted your photos from your computer, it ALSO deleted them from your 'shared' sites; eg, Facebook or whatever. To me, this was absolutely asinine behavior as many of us use multiple computers, can't store our entire photo libraries on them at all times, and so on. For example, my workflow is to take a lightweight laptop with me when I travel, and the SSD can't hold my whole photo library; just enough to do quick edits, upload, then delete.

I'll have to experiment with Photos' 'sharing' support, but I'm afraid of breaking stuff from past experiences.

(I also think it’s entirely reasonable to only have the thumbnail bar for photo navigation. I think the one in iPhoto worked exactly the same? It just maybe wasn’t displayed by default? If you give it all the functionality of all the other views there are consequences to that, knock on effects. For example, which image should be displayed enlarged if you select more than one in the bar? Keeping it simple keeps it simple.)