For what it is worth, for 10 years I towed my old 30' Trail Bay (5333 dry weight) with my previous TV, an '03 F-150 (5.4L 3.73). On trips I was probably towing 7000-7500 lbs. Within my TV's capabilities.
Have read that the new 1/2 ton F-150's have more power than my old truck. At any rate that trusty old TV worked really hard, got us where we were going, but just wasn't an enjoyable experience anymore - was contemplating getting rid of the whole shooting match.. I traded my 1/2 ton Ford in for a used '11 Chevy 3/4 ton Duramax diesel a couple years ago. What a difference. Towing was actually fun again. Yes, New diesels are expensive , but buying a good used one was affordable for me.
My point? It's way better to be over-powered than under-powered. Have never personally towed with the newer Ford 1/2 tons, but with my awesome 3/4 ton diesel I have nodesire to ever go back there.