A few ideas:
* Don't just list full custom STEEM libs, but also more generic libs for JSON-RPC, base58, etc.
* Remove libraries with repos that have been inactive for a long time. Maybe a cleanup after HF(n ) of all libs not updated since HF(n-1).
* For languages where this makes sense, distinguish between blocking/synchronous libs and non-blocking asynchronous.
* Per language (+ lib attributes), create an API completeness matrix, one column per lib, one for per set of related API calls or other API feature, error handling, etc.
* Do the same with API nodes as columns.
* Keep an up to date (hours) list of API nodes and publish their specific stack, availability stats, etc in both a user friendly view and in a JSON variant. List should include info on failure model, rate limit implementation, batch support, etc.
* Link to @utopian-io posts about the libraries.
* Create resources describing the different options for implementing user authentication and/or user authorized operations (KeyChain, micro transactions with, custom JSON Auth, that Google bridge thing (forgot it's name), SteemConnect, using the users posting key, etc) again with a matrix showing advantages and drawbacks of the different options.
* A register for description of custom JSON based layers on top of STEEM
* If it exists: information on anything smart-contract related for the STEEM blockchain.

Hope this is the kind of input you were looking for.