Most american tourist trips to Europe sound the same to me: run run run - the more countries the better... I know it's smaller in scale than the US so you think it's doable, but in terms of diversity it's like saying : USA + Mexico + China in 4 days. It's exhausting... and IMO you miss out...
Not questioning the details, but I would plan to visit about 1/2 of what you plan, skip one country altogether (your choice) and chill / enjoy where I'm at a bit longer.
Now as a specific item, most people focus on the known areas - in France I'd recommend getting off the beaten path and visiting Carcassonne for something different.
Carcassonne - Wikipedia, the free encyclopedia
A real intact fortified medieval city - not the mickey mouse kind. Amazing sights, good food, nice region... Very cool and different from the frou-frou castles of later centuries - very cool guided tours where they explain all the tricks used to kill knights in armor, where to pour boiling oil, how to make them trip down stairs, best tour I'd experienced in the country... that is all ;- )