My mod was removed from the site for being too popular and not technically a mod, so I am creating a thread here so people have a place to post feedback, bugs, and suggestions.
I downloaded every SE mod from Nexus Mods, extracted the plugins, and recorded the cell edits in every plugin. Then, I used the UESP skyrim map tiles to display all of the edits as a heatmap.
You can click on a cell to see all of the mods that edit that cell sorted by popularity. Clicking on a mod in that list will show you all of the cells that the mod edits (across all files and versions of the mod). You can also search for a mod by name or a cell by x and y coordinates in the search bar at the top.
All of the code for this is open source:
modmapper: program to automate downloading, extracting, and parsing plugins
modmapper-web: website code for displaying the cell edits as a heatmap on a mapboxgl map
skyrim-cell-dump: library for parsing skyrim plugin files and extracting CELL data
Anyways, hope this is useful to others. I thought it was pretty interesting to see the most popular places for modding in Skyrim.
I'm now keeping track of features I'm working on on this Trello board.