Wet fleece insulates, a whole lot better than bare wet skin but,Wet wool is still the best for heat generating/retention,as far as Wet fabric is concerned!Drying is a trade off of sorts-Would you rather be Warm & wet or Dry & cold? Start up that campfire to dry up/warm up a bit,I'll take the wool!Merino,Cashmere,Alpaca in that order if I have a choice! For fleece I would choose Patagonia capilene or Medalist micro as,I have some & they perform well,also!All of the above are, Money well spent,IMO! I have no affiliation with the above mentioned brands,chingaderas,etc.

I prefer fleece, fiber pile and holofil over wool for 99% of my needs. It's warmer, lighter and much easier to maintain. Modern synthetics are not actually easy to ignite. They tend to melt rather than burn.
Having said that: If I know that I am about to light a fire, I have a wool Swanndri to wear as a top layer.

i have a few old books about trapping and canoeing and of course wool was the only thing they had,a old suit jacket that went "shabby" was a good choice among campers and fly fisherman.i did not see much in the way of rain gear.top and bottom rain suits seem unknown and waxed overcoats were heavy and expensive.
so to the point,with fleece or poly fluff of some sort and modern rain gear you have all the good points of wool beat by a mile.warm,dry and light rather than wet and heavy.when you have wool on and it's keeping you warm when it's wet you are burning up lots of calories to do that.energy best used for what you are out in the weather doing.

For me: I'll take the leather oxfords with gaiters, fuzzy wool pants, white cotton shirt, canvas peacoat, and beaver felt hat.....

Byrd...Great Picture!!! 'thats the problem with the old days heavy,clunky clothes and no auto ejectors on the shotguns.

Pure wool thermal underwear and socks, thank you. One or two layers under my wind / water proof shell, depending on temperature and expected intensity of activity.

I also carry the additionional fleece sweather or jacket for my lunch break needs.

Ditto -- It's not an either/or question, both have their strong points. I like pure Merino wool next to skin. Layered above that will be either another layer of wool or poly fleece; if it's cold enough a layer of wool and a layer of poly fleece. There may be an outer layer depending on condition and circumstances. That outer layer can be nylon or wool -- depending. It's very situation driven. Pants will be merino wool long u/w under nylon or fleece pants. Socks is wool and wool, liners and socks under boots.

Big Ditto on that statement! It's all about proper Layers, and a base layer of Merino wool is a great Start, then a fleece, then a shell (dictated by the conditions).. I have yet to burst into flames next to a fire, and have been around PLEANTY.

I think the most practical application of the non flammable properties of natural fibers is the wearing of naturals as the layer next to the body when in a situation (like flying in small planes) where the possibility of dealing with a significant fire exists. I am told (and I don't know of any objective studies) that synthetics will melt on the skin and cause significant injury - injuries that do not result if natural fibers are next to the skin.

The biggest problem with synthetics around campfires is the damage to the very expensive garment, not to the wearer. I don't know of any instances of injury from a campfire involving synthetics as a significant factor. Does anyone else?

Overall, I think the most significant advantage of synthetics is their inability to absorb moisture. They can be wrung dry, worn immediately, with final drying resulting from body heat. Wool is good; it's just that synthetics are slightly better. Cotton is a different story.....

Wool dangerous in cold weather water sports.

Almost lost a scoutmaster when his layers of Filson wool
drug him to the bottom in a canoeing flip.

Also heavy wool layers leave rafters floating much lower
when out of the raft. They hit more rocks and inhale more
water.

The stuff doesn't dry for a loooong time too.

Polypro adds buoyancy.