Any feature which even slightly dilute the celebrity worship culture and functionality imposed on a thriving G+ community in early September would be a positive step. A glance at the results of your Most Popular Posts reveals the domination of a very few pop culture celebrities and Google-promoted pseudo-celebrities, turning G+ into an artificially exclusive and effectively closed environment, rather than an open and inclusive community able to select its own leaders and content. Do the Most Popular Posts represent the best contributors of the best content out of the 150+ million participants on a daily basis? No way. There would be far more new users represented, and far more outside of the Top 100 or Top 500 cliques.
So I think there are two valid answers to your question. Yes, such a feature could help many G+ members "do better" with their social and professional networking on G+. But when you look at a specific population of participants, for example photographers, and consider that out of the tens of thousands of photographers on the site the 500th photographer has has been circled by about 16,000 people compared to the top Google-promoted one being circled by nearly 2 million, it's clear that the only way to truly succeed on Google+ is to be chosen by Google, to be promoted by Google as one of the "Fun and Interesting" people on Google+, to the right of everyone's Home stream. Here's the impact on the community of photographers who have helped G+ thrive:
Note the interesting and significant fall-off around places 30 to 40 on the list, where circle follower count suddenly drops from about 1 million to around 60,000 or less.
This special status and the additional contacts gifted by Google leads to more views of posts, more comments, +1s, and shares, being featured far more often in What's Hot, which also results in far greater selection in +Jarek Klimek
's selection of top G+ photos, greater likelihood of being chosen to speak at the Google+ Photography Conference being organized by +Scott Kelby
, being featured on various Internet shows, etc.
So that leads to the second valid answer to your question: no, tools to study post effectiveness are unnecessary, since individual action on G+ tends to be pretty worthless while even the more successful people in the community lag Google's picks by a ratio of over 100-to-1 (and getting worse by the week), and while all other site functionality and the off-site additions to the Google+ environment naturally flock to feed off the networks artificially awarded by Google, and further promote and glorify the artificially imposed state of unbalance.
This does all point to an interesting opportunity that has gone unaddressed: content discovery features which help highlight better content, beyond the few people Google has had the time to promote. Such tools would be of far more interest to the community, and would help the G+ community thrive. For example, an alternative to What's Hot, without the Google-introduced bias. Calculate the most interesting posts, but discount them by circle/follower count. Whose posts are really the most interesting on Google+? It would be fascinating to explore.+Jari Huomo
has implemented a number of interesting features such as various ways to process and display their own timeline, or the posts of others: http://www.googleplussuomi.com/photos.php?id=107459220492917008623
An interesting and fun feature might be to enable G+ community members to compare their best posts against the best of others, sort of a "Celebrity Death Match" format. A simple display of posts in two columns side by side would be an interesting enough feature that I think people might have some fun with, like this but comparing two users: http://www.googleplussuomi.com/timelinetest.php?googleid=107459220492917008623&sort=best
Additional unique value could be added by enabling users to vote, and when Top 500 celebrities and their posts come up in your site's searches the future, there's now additional value-added data to provide: "If you like this user or post, here's another one that community members have told us that you might like even more". Such a feature could help turn the community back over to the community, one post and vote at a time, helping make G+ more open to all participants.
Why would these features interesting enhancement go G+? Psychology offers answers:What makes people happy
"According to the selfdete rmination theory, all humans have three basic psychological needs: the need to belong or feel connected, the need to feel competent, and the need for autonomy or self determination. 'When those needs are satisfied, we're motivated. productive and happy. When they are thwarted, our motivation, productivity and happiness plummet,' Prof Ryan says.http://www.rochester.edu/news/pdfs/RichTSTb.pdf
Community members want to select their own connections, they want an equal shot at opportunities to be recognized as competent, and they want complete autonomy, not to have their actions, network growth or connections dictated to them (even indirectly by ubiquitous domination onsite and offsite by the same few dozen people in their field). Content discovery, rating and recommendation features would help users take control of their use of the site (give them the autonomy they crave) and provide them with the bonus of seeing better content.