The big reason for larger rims, same diam tire is the brake rotors are bigger.
A couple of other things NOT mentioned so far.
Braking distance is lowered some, probably 5' with 70's vs 75's. As the sidewall is shorter, less shrinking, so braking is better. Same with take off, and traveling, so mpg's are better. Probably a .1-.3 better......but from a manufacture stand point with CAFE points on the line. that can be a lot!
From a driver but stand point, none of the things mentioned are probably super noticeable.
One thing I have personally noticed when switching from higher profile tires to lower, is the front tires do not wear on the outside as bad with lower profile tires. So I get a few more miles per tire set. This is probably because I do a lot of city driving, so more turning, more wear on the front tires, vs some that do mostly interstate straight run driving do not have this issue.
Another problem as noted, one may have to go up a load range to carry the same load, as the load is not carried by the tire itself, but the air inside the tire! This is noted in the 17' vs 16" 300 lbs less for the 17. A D rated 16" is rated to 3000 lbs, or closer to the 17" 3100 lbs rating than the E rated 16" equal at 3400.
For 2112, I would not go to E rated tires on your truck, D or C rated maybe depending upon the payload pkg on your F150. One does not need 12K lbs of tire capacity on a rig usually with 6600-7200 or so lbs of gvw. You will be traveling at 30-40 lbs of psi in the tire, so spend less, take wife out to dinner, and get the lower load range tires of equal size.
Marty