In practice there is not a lot of guidance for theme selection, even though it is an important choice. And while some themes will offer a refund if not right, there is no ability to test out the theme in advance to see how it looks or behaves with your needs/content.
It would be useful to know something in advance about documentation, code legibility, support responsiveness, as well as about whether particular features are present or work well.
At the same time, there is not a lot of ‘social’ activity around themes. Specific discussion on the forum is limited. Rankings/Ratings on ThemeForest are sparse. There are quite a lot of general review lists of themes, but they do not seem very current/detailed.
The Ghost Marketplace may not have the scale of some ecommerce platforms, but it is unusual to see a venue like this that does not allow for some ranking/rating/discussion. We have become accustomed to such activity in AirBNB, Uber, Amazon and so on. Would it be useful to add some of this rating/commenting/discussion capacity to the marketplace?
Of course such activity needs to emerge from need/interest, and does need some scale. Maybe the community is too small? Is it worth trying though? I certainly would be interested in more signals when thinking about theme selection and migration.