I love it!
A suggestion for much further down the line: a timeline on the map which composites many maps from a similar time period so you can see them all stitched together (somewhat like how https://skyvector.com/ stitches together multiple sectional charts into a continuous map, though I know it can't be as seamless).
Or you could attempt to run some extra processing steps to warp the map to match the background map's projection.
Those are both big undertakings, though.
Very doable, these are called mosaics in the GIS world and it's actually not that crazy to do
Really love this suggestion, I could see it making map exploration far easier since now you just need to explore by year instead of by map and by year (reducing dimensionality by 1!). Thank you, I'm going to chew on this a bit more but I really think there's something here
