Time for a decent cooler. Wool or fleece?

You are not being a Contrarian.
In my barn we are not putting coolers on hot horses. Just wet ones. I do put a cooler on a horse if I’m concerned about them getting a bit hot and sweaty in a situation such as being trailered or after they have been tranq’d by a vet for some reason (in the winter–summer I let them sweat).