I noticed a thread recently and thought I’d share my experience.
I’m a moderate climber/ski
I wanted a boot to climb more than ski so bought the procline.
It was great for climbing and I led hard mixed on Temps de Assassin? On the Tacul. Didn’t ski any hard stuff but no issues with heavy sac on Mer de Glacé or heading to Argienterre hut.
However on the Swiss Route on the Courtes in Feb left me with such frozen feet that I did get some frostbite.
They do ski and climb well but at a major compromise on warmth.
People of harder stuff may do better.
I find this the same with the Atomic Backland Carbons. Tried the Salomon MTN Explores and they are much warmer, but also heavier and definitely focused on downhill rather than skinning/climbing. The Backland Carbons felt very similar to the Proclines but slightly better suited for downhill (and for my fat feet), I've read that adding one of the thick warm Intuition liners solves the cold-feet problem as well as providing substantially better calf support.
It's a (currently) inevitable drawback of having incredibly lightweight flexible boots, the materials to achieve the spec are just terrible insulators. Swapping out the liner for something heavy-duty and using an ultra-thin merino liner under your boot sock is the only alternative. Just watch the sizing when moving to a thicker liner.