You're totally right, and unfortunately, it's not possible on a blockchain to replicate the experience standards set by the likes of Reddit, Twitter, Medium etc. A partial solution, as you pointed out, is to build centralized frontends on top of the blockchain. That can effectively solve the user accounts, moderation and curation problems. However, that will still be far behind on performance and scalability, as one has to rely on the very slow and extremely inefficient Steem blockchain.