GT winners are rarely the best overall rider. You'd probably have to get 10 minute bonuses on flat sprint stages, and have some classic like stages in the GT for that ( cobbles, long hilly stages like LBL design). Climbing and time trialing are only two aspects of the sport. A route with lots of time trialing just gives you the best time trialist who doesn't die in the mountains as the winner.
Based on that logic let's see a Mont du Chat downhill TT.