Stage 6 is very weird. Furka is a very nice pass, almost 17 km with mostly fair gradients but a steep section towards the end and a very challenging descent on that side. You can make such a nice stage in that area: Gotthard (2100 m), Nufenen (2500 m), Furka (2450 m), finish in Realp. That would really kick ass - short, 3 2000m+ passes and hardly any valley.