sliding off a cliff at 1/2mph without being able to control looks like a situation where not even mud tires wouldve saved you, but you'll probably never know. Glad you're OK.
There is a noticeable difference in performance between a HT tire and a MT one. AT Tires are a gray area that will lean toward one or the other depending on the aggressiveness of the tread, obviously. This applies to manners, wear, etc.
If you want a lighter tire, and your truck is on the lighter side as well, you can get away with Load C Tires. You'll cut down in weight significantly vs E rated tires. But this will generally leave you with less options sizewise. What size are you looking for?
I don't recall exact numbers, but my Toyo AT2s were about 10lbs lighter per tire in 265/75R16 vs the E rated version. I really like performance of these tires both on the road as well as off road. I can highly recommend them. (My normal trips are about 900kms on road and 400 off)