Isn't the unique feature which distinguishes HIVE from other blockchains/crypto currencies the social aspect (where it's main advantage compared to conventional platforms like facebook is that authors are getting paid for their work; plus censorship resistance)?
Yes. It is its very identity.
In my opinion user retention only doesn't work because (manual) curation doesn't work!
There are many other impediments, including the difficulty of creating an account and the overall complexity of the platform.
I had written about that here and here, and just recently got involved in an interesting discussion with @blocktrades.
Thanks for the links. I'll check them out.
In short: the manual curator who upvotes later than all the auto voters is disadvantaged on HIVE because of several reasons, for example the short curation window. It's more beneficial to upvote popular authors again and again instead to seek for new authors or also check the posts of long term but less popular users to encourage them to improve.
That's actually a misunderstanding. When you upvote popular authors, you're going to have to share your curation rewards with a larger number of other curators. In fact, this is why @acidyo had @reward.app created. He said too many large curators eschew voting on those posts that already have many votes on them because it means lower curation rewards, which is a problem according to him because it means many of the best authors are left without the large rewards that they deserve.
Also, remember some of the most powerful curators on the platform, @appreciator, @rocky1, and @upmewhale are engaged in active manual curation just for that purpose: user retention.
If we removed the global rewards pool what would then still be the incentive for the average blogger to join HIVE?
Censorship resistance, although the average blogger will never need it. Only those who write about topics that are controversial enough to deter advertisers.