I think having an easier way to drop comments and sign up (e.g. through google/facebook login) will be great for adoption. Basically to lower the learning curve for people to get started with their first post.
I also think there should be a on-chain way for users to categorize their content into the various types (e.g. long Medium-like posts, short Twitter-like posts, image based Instagram-like posts, sharing of external articles, video-based content and etc). If we have such on-chain data, it will be easier for interfaces or dApps, to be built around those content types. Of course, this heavily relies on users categorizing their content correctly. But it may evolves into the specific interfaces categorizing the content by default. For example, if you post through Peakd.com, your content is by default a long blog post. This will aid in content discovery and dApp building in my opinion.