I noticed in the new roadmap that the second item on the list relates to "Pandas DataFrames and SparseDataFrames". I wanted to mention that according to an August 2018 talk by @datapythonista (who is a pandas core contributor), SparseDataFrames will be deprecated. Here are the slides from the talk (in notebook form).

I mentioned this to @amueller on Twitter, and he suggested opening an issue to document this.

This PR seems to be the most up-to-date discussion among the pandas team about deprecation.

Hope this is helpful!