Quick redesign, with thanks to the people at LaFlammeRouge for their attempt at tracing the route based on the animations:
Stage 1-4: no change
Stage 5: add 30-50 flat kilometres at the start, haven't bothered to draw a new profile
Stage 6:
The route crosses the border five times, four of which in the final 55 kilometres of the race. The first 170 kilometres and the final two climbs have been retained, but a few steep climbs have been added in between to make for a real Ardennes stage.
Stage 7:
Added Chevrères, removed the gravel ramp.
Stage 8: no change
Stage 9:
Uphill start, something really missing in the actual route, to the Col des Mosses from the opposite (hard) side, then looping through German-speaking territory to climb the Col du Pillon before temporarily rejoining the actual route over Col de la Croix. The Montée des Giettes, with its steep first half, adds some spice to the pointy end of the stage; the finale has been retained in full. (the finish could be 5k closer to Pas de Morgins but I like this finale, it has Pescocostanzo vibes).
Stage 10:
A much tougher first part of the stage, with two borderline cat.1/2 climbs, then relatively easy in the middle before the final combination of the classic Côte de Domancy and the irregular Montée de Vauvray, using older roads to Combloux and then Megève. It's possible to continue to the altiport; I preferred the finish this way earlier tonight but now I'm not sure.
Rest day here instead of a day earlier, makes more sense, also given that it's the second rest day and not the first
Stage 11:
Added the duo of Champ-Laurent and Grand Cucheron. Madeleine isn't that realistic in this day and age; this is still a worthy queen stage, imo.
Stage 12:
Glandon instead of Croix de Fer, we rarely see it in combination with Alpe d'Huez and it's a better climb anyway. Would prefer to climb Huez via Villard-Reculas but that will never happen for financial reasons. I have slightly shortened the flat through the Oisans valley by taking the D44A and D44 from the dam.
Stage 13-15: no change. The first is a sprint, which is fine at this point, it's difficult to change the run-in to Mende, and Stage 15 is nicely balanced (if the LFR reconstruction is correct) so that the break is favoured but stronger sprinters can win in a 2020-esque edition, somewhat akin to the Lyon stage of that year.
Stage 16:
Flipped the order of the Pyrenees finishes, this takes a long stage to Peyragudes to work. As it's mostly a leg-softener this way, I've chosen to retain the altiport finish.
Stage 17:
The original route of stage 18. The short length fits well after a long stage 16 and the final combination can't be improved anyway.
Stage 18:
A much more attackable final mountain stage, with little flat between the climbs and a descent finish in an actually-appropriate slot.
Stage 19-21: no change