I would be OK with aluminum body on a truck. But I'm not the guy that nitpicks hail damage and scuffs. I keep mine clean and take good care of it, but it's not a show queen in front of a tailgate party either. I just use it. If the paint gets knocked off, I'll touch it up, but I've never been one to worry about dings and dents unless they'd risk rust -- those I'd fix.
So, a thicker, more dent-resistant, rust proof (note Al does corrode), body that assists mpg? I'm just fine with it.
backup cameras, proximity sensors, eyeball detection, blind zone protection, car2car network -- I will hold off as long as I can. My HVAC controls on the 2006 are still push/pull cables. While I wouldn't mind something a little more current than THAT, I gotta admit it's been nice having a trouble-free vehicle in this one.
But Al, yea, I think it's fine. Last jeep GC had an Al hood and I never had any problems with it. The T&C in my sig has a MASSIVE Al subframe -- the engine carrier, ties the lower front end together -- suspension, steering, engine/trans mount, all mount to it. Supposedly it is the largest aluminum subcomponent manufactured for a vehicle to date (don't know how dated that statement is), and IIRC it was a big factor in reducing chassis flex as well.
By the time I can afford an Al-bodied F150, there will be plenty of history on real cost of ownership and repair.