I felted a wool blanket and used it a couple of nights in 30F (+/-). It worked well excepted for a couple of things.

I doubled the blanket over and just laid on it..no pocket in my HH for it so while it did shift a bit, it was not bad but at about 24" it was too narrow. Therefore my shoulders were cold most of the night even with Poly LJ, wool sock, and a hat on. Shoulder still got cold enough to wake me up a lot.

The 2nd item was weight. Wool, while a great insulator, is heavy compared to newer materials. I was motorcycle camping so weight was not an issue but I sure would not carry it far.