Hi,
I also will put some work into documentation. I start with Arcade cores, that needs updates to all readme's that still refer to the old rom concept. So I made a proposal to Asteroids readme to reflect the new version and more importantly point to the correct wiki page for this part of the existing documentation.
This step should make maintaining the cores more easy as only one page need to be updated vs. all the cores in the future.
Let me know what else needs work on on the documentation front.
I also plan to create a tutorial core based on the "nand2tetris" project
https://www.nand2tetris.org/
I started with the nand2tetris project to understand fpga design, and now getting into vhdl. From there I need to understand how to implement the very simple computer on the MiSTer hardware to do the same as the software simulator. I will create that now in my own github account and repo, but evtl. want to merge it here for others to learn from it.
I believe MiSTer is also a fantastic learning platform. It just needs some documented real world tutorial with a very simple use case to understand the concepts.