Good thread. Useful links there Ben, many thanks.
There are definitely climbs out there that haven't been used. But mostly they have to do with logistics. Getting officials there, lodging for everyone, etc. For example, I'd love to see them go back to the Puy du Dome, but I realize with so little room at the top, and it being a national park, it's less and less likely to happen.
I don't think this year's Giro stage to Val di Fassa is inhumane. The entire Giro is going to be difficult and the most climbing probably in a few years, even though the Giro is often for climbers anyway. But I don't think it's too much. I don't even know if the Fassa stage is more brutal than the
2009 Stage 16 to Monte Petrano that had almost no flats, and was raced in stifling heat. It one came after a tough previous mountain day as well.