1. Sharing lacks exclusions. You can't say "Share with this group, except these people" or "share with this circle except people who are in this circle". This is possible on Facebook and makes the whole "selective privacy" thing actually work. When people think of privacy, they think about who they don't want seeing their post(s).

2. From the start, there should have been the ability for users to publish their interests as circles that people can choose to selectively subscribe to. The effect of this change would have been MASSIVE. Although I've added hundreds of photographers to a photography circle, I can't exclusively see their photos... browsing my photography circle is a bunch of personal posts and political posts, etc. They fucked up the entire idea of categorization. Months later, Pinterest came along with the right idea, where you can follow an individual's interests rather than the person themself. This makes your own homepage FAR more relevant to your interests.

3. It's still not personal enough... it doesn't encourage messaging/sharing between individuals. It's a content network rather than a communications network. That's why they won't get Facebook users; they don't serve the same purpose. People use Facebook as a communication medium. They use it as a contact list, birthday calendar, and for events... Google+ has none of these.

4. By not having an API, Google+ is not being integrated into the rest of the social apps on the/any market. As soon as they have that, it is free advertising and will be shown to people as a viable alternative to the platforms that they are already using.

5. A lot of small things, too. For some stupid reason they hid all the circles on the front page that everyone painstakingly created, and put them behind a menu. There's still no "public posts near me" on the desktop app. "Explore" is a global-wide popularity index, rather than one from your own circles/interests (it's been really shitty lately, and I wish they gave an option for the other method). They don't allow you to edit the title and description of web links like you can on facebook... which makes the quality of posts poor. They also haven't yet integrated their other products into the ecosystem yet, like calendar, docs, drive, etc.

The list goes on.

My posts can get lots of shares and +1's sometimes, which makes it my preferred network to post my photography on... but that doesn't mean that I like what they've done with the place. It's a horrid mess.