I think the route is alright. The one striking issue is obviously the ridiculous lack of (flat) TT kilometres. But to be honest, if that TT was significantly longer I would actually like the route and with the two likely main protagonists being fairly equally matched in TT's the length of that stage probably won't have that big of an impact on the remaining race anyway.
But aside from that, I like the early pyrenees mountain stages, which aren't brutal but hard enough for the middle of the first week. I really like the return of Puy de Dome, especially as stage 9 which is the perfect spot for that kind of mtf.
The triple of mountain stages to end week 2 is decent as well, although I don't really like stage 15. But as that stage doesn't look particularly hard it at least shouldn't hamper the two stages preceeding it. (Quick note, I'm fine with Colombiere as it is, but the fact that they still refuse to properly use its hard side is nontheless really infuriating)
Stage 17 is alright, much better than a Col de la Loze mtf, but I'm still sad the ASO is yet to use their new shiny toy a bit further out. I guess this is also the point where I should mention that I'm altogether disappointed by the complete lack of a proper queen stage. Finally stage 20 is really good and imo the best final mountain stage in a long time. Not insanely hard but because of that forcing riders to attack in the earlier stages while still giving a good opportunity to do an all or nothing attack.
Concerning too many flat stages, I somewhat agree, but at least many of the flat stages come later than in previous years. For example I don't think that stage 18 will be an uncontested sprint stage, coming after the hardest day of the race. For similar reasons I think the sprinter teams might have a harder time to control breaks in a few stages.
Altogether a decent route that could have been drastically improved by a long ITT and a proper queen stage.