Too funny. I started to go down your path in a response, but decided not to. Since you lead the way, however I'll choose this opportunity to chime in!
You're right on target - frontal area and drag coefficient are a linear relationship to total drag load, speed is a quadratic (much more impact). The reality is that the pointy nose (oblique angle) of a boat may NOT be substantially different than the overall drag coefficient presented by the towed enclosed trailer. Yes, a blunt 'square' perpendicular profile of a typical enclosed trailer is about as bad of an aerodynamic profile (i.e. drag coefficient) as you can get; however a typical boat has enough crap sticking out there (like a center console, top, whatever) such that it may not be all that much better off.
The bottom line is these vehicles can tow a lot. Keep good oil in them and you'll be fine. I've run in excess of 15K mile oil change intervals (synthetic) on my '12 Expedition. Each oil analysis says all is fine. I don't have the towing package (additional coolers), I tow a boat in excess of 6000# to the keys once a year in the middle of the summer. I am just now changing my transmission fluid out at over 100K miles (3 bleed and feed evolutions). Albeit brown at the first drain - no smell, no issue. The car is great. I've run extended intervals on all my vehicles (tow vehicles included) for all of my adult life (at least once or twice backed by oil analysis for each car) and vehicles have tested fine with no degradation in oil specifications. We're talking since 1983.
I must say that I believe the 3.0L turbo is likely taxed, but the transmissions are certainly rated for the duty. I had an '84 Turbo GT Mustang that I drove at the track quite a bit (road coarse) with synthetic oil (Amsoil in the day). It was a 2.3L turbo I eventually intercooled with 15 lbs. of boost. The first time I put an oil temperature gauge on it I about $hit a brick - I hit 300 degrees oil temp in 3 laps! Shortly thereafter I put an oil cooler in. At 80K miles (likely 7K of which were on race tracks) I finally blew a head gasket AND the turbo exhaust housing was cracked (whistled for a while). When I pulled the heads off I could still see the OEM cross-hatching in the cylinder bores. I swapped the head gasket, put on a new turbo exhaust housing and back together. It ran great for many more miles. I can't imagine the Aviator (with todays advanced technology) is taxing the 3L motor any more than I did my 2.3 36 years ago.
As long as you follow the OEM warning as to when to change - you'll be fine. If you're really anxious - run synthetic oil (and they're all excellent these days - I just stocked up on Kirkland at a very reasonable price).
