I agree! Steem is a social media hub and should be treated as such. As you pointed out there are many examples like Zappl and Steepshot that could be used like that and surely will. The unwritten etiquette we have today will transform and adopt as more diversification comes to the blockchain.
In regards to OnStellar that is not meant as a quick sharing platform but as creating really valuable content for eternity. I think over there we will have a very different approach to that but I am not sure how they will handle this. But they will also be prone to more platforms coming in and handle the ONST token in a different way.