I think it's fair to question the stage design and to consider overall changes to the approach of the first GT week. Maybe have always a Prologue and then 1-2 stages with super boring highway stages? Maybe introduce crazy regulations like last 20k on a flat stage everyone gets the same time? I don't know.
But overall, the blame is being too easily shifted on the UCI and ASO in my opinion. The way teams approach these stages nowadays is just as much to blame. Riders are waaaay too nervous and everyone is super aggressive, if you have 5 GC teams and 5 sprint teams wanting to be at the front you gonna get carnage either way, doesn't matter if the roads are wide or without turns. Every team wants the spotlight and the financial advantages of the Tour but if you're gonna have multiple stages rolling along flat highways no one is gonna watch and the value will drop.
Plenty of cycling fans have also quite some double standards. So many people want crazy cobble stages included in GTs, before the gravel stage in the Giro everyone was hoping for rain and everyone was yawning when they had the 170km flat in a line stage. But then after unexpected crashes everyone throws their toys out of pram.
Yes this final was quite twisted but I also didn't see something outrageously dangerous. No change of surface, no weird road furniture, no crazy round abouts. 2 crashes because riders clipped wheels/were too aggressive and one because of a curve that didn't look insanely sharp.
Too early at this point in the tour? Maybe - insanely dangerous? I wouldn't say so.
We all know what the riders will do. Year after year we see the riders rush to the front on stages like this. Now if we can see it, why can't the UCI and ASO, and if they have, why have they not done something about it to make things safer or dissuade riders/teams from doing it. By not doing anything, they encourage it.