I use wool as a mid layer all winter, used between a wickable inner and a windproof outer. I really like thin jumpers and sleeveless pullovers for fine-tuning the insulation.
My fav wool is Alpaca, it has hollow fibres so retains its insualting properties when damp . Ive never had a wet wooly, even in the rain.
As an outer layers,Im not sure its so good. Harris Tweed is a very tough material, and handles water quite well. It used to be the material of choice for gentlemen cyclists in the early days, and is de-rigeur if you ride a Penny Farthing (Ordinary Bicycle).
Ive ridden in my tweed jacket around town. Tweed trousers may be good on very cold damp days, if you need to look smart at the end of the ride. Before I wore a helmet, a tweed deerstaker hat served me very well.