There has been ample coverage of Google+ and it's growth or lack of it. So much so, that I won't even bother linking to any. Everyone knows that Google+ is not heavily used when compared to usage rates from Facebook. From my personal vantage point, Twitter and Facebook still attract more users more quickly than Google+. Many who tried Google+ early on have given up on it. I'm not sure that Google+ usage compares favorably to the current usage of prior internet darlings MySpace and Friendster.
When Google rolled Google+ out, it seemed like they wanted people to jump from Blogger to Google+. This would stem the losses to Twitter and Facebook. I recall seeing hearsay that Blogger would be eliminated. Fortunately, that has not come to pass.
To me, the nice thing about Blogger is that it is possible to get some return from your effort. Ashdar Partners has not made a dime directly from this blog. Being who I am, I like numbers and measurements. I do look at the blog's statistics from time to time. The fact that anyone at all looks at these pages for any reason is encouraging to me.
As far as I know, there is no way to see if anyone is reading Google+ posts unless they "+1" the post or leave a commentary. There is no aggregated reporting on those attributes. It doesn't seem possible to ask a question like "Which of my posts has the most +1's?". For people who are full-time bloggers (rather than running one as a sideshow) or who have multiple blogs the ability to judge reader interest in particular topics is critical and guides what they blog about.
I can see if anyone reads Blogger posts, even if they don't leave commentary. There are nice reports, with drill-down items. The only metric that Google+ seems to surface is "followers", which doesn't provide me with a number that I can get excited about.
So, with respect to improving the usage of Google+, I have two suggestions. I will go with the obvious one first.
Google should provide a way to monetize Google+ postings. I know that I'd be more likely to post if I thought that I could get something out of it and my posting wasn't going to be just another data source being collected by Google in order to market me to other companies. It doesn't have to be a huge reward. Only a few dollars a year or even just an occasional free coffee at Starbucks or even Dunkin' Donuts would make it seem more worthwhile.
I think that the economic aspect would tempt a lot of people. The downside on this is that it would cost Google something. It might not be a lot, but it would be more than they are spending now.
I think that my second suggestion would tempt fewer people but those people are the ones that tend to take their blogs and online prescence more seriously.
Google should provide analytics on Google+. They do it for Blogger and my recollection is that this facility has only improved over the years. I presume that Google is collecting and aggregating similar statistics on Google+ postings for their own use. I couldn't be too hard to surface that data so that Google+ users could see what generates user interest.
In short, if Google want Google+ to supplant Blogger, Google+ should provide all of the features of Blogger plus new features that make Google+ better than Blogger. They have not achieved that, yet.