I am a little undecided. I also do love this style, and I think you have done very well in bringing over the flair.

But there are some, more or less minor, details that reduce my enthusiasm for this particular work. Of course, if your commisioner is happy with it, who am I to critisize? But nonetheless...

First of all I would disagree with your basic decision to "avoid to clutter a map with the borders evolution". Showing changing borders, by a differentiation in hatching or colouring, would be a lot better suited to show the "rise" and "decline". Two or three maps would have been sufficient, and would have kept the "clutter" at a minimum.

Second, I think that the placement and style of the map-grid labels right in the border was a bad choice. It breaks up the overall image and draws unnecessary attention to the border, away from the map.

Third, you re-used paper textures for half of the maps. Perhaps it is only noticeable because of the way they are grouped here, but it should not be noticeable at all!