Some of this you have covered some maybe not but remember things dont always perform at a level that equals the specsheet.
So....To play devil's advocate.
Obviously every truck is going to come with compromise's it seems as though you are looking more at problems without much thought to how complicated the solutions are.
A few examples
Although not commonly in stock at the local tire store's chain's for larger tires are very available online and are usually better built because they are for industrial applications like construction and mining.
The wheel spacers for the tundra are available but they do cause some other problems with tire scrub while turning (i can elaborate) and accelerated bearing and ball joint wear. The same problem's exist with offset wheels.
Most open rear diffs have a aftermarket selectable locker available.
When you think of clearance there are other considerations than the factory numbers
First the break over clearance, approach and departure angles. This can be changed with a small lift just dont go cheep.
Also you must consider a few other things
rear differential clearance.
Rear shock brackets hanging below axle tube?
These can only be changed by adding larger tires.
Is the axle high pinion or low pinion?
This will dictate whether or not you turn your rear driveshaft into a pretzel on a rock and try to go home in front wheel drive.
You mentioned larger tires affecting the torque applied to the ground. This will have so many variables if you mean on the road than engine out put and final drive ratio will dictate whether or not a f150 on 33" tall tires will apply more torque than a tundra on stocker's(it very likely will). If you mean torque applied in low range than you would need to multiply engine torque through the first gear of the transmission then the transfer case low ratio and finally the rear axle ratio to get your crawl ratio of each. This is all for not for two reasons first on an auto the torque converter has the ability to multiply the number in incalculable ways and second most manufacturers are derating power when trucks are in low range to make the drivetrains survive through warranty
I have a suspicion you deal in this trade, or it seems that way, based on the insightful comments you provided here. Talking to a friend in the after-market business, he mentioned many of the same things you did. After a lot of discussion I went back to the drawing board to see what I absolutely need and what I don't, Thanks to his input, it resulted in me wanting to do as few "after-market" upgrades as possible. Both for price and for practicality.
He helped me sort it out to this, as far as after-market work this truck will have:
1. 2" lift. No more than that. To many other complications come into play when you go higher than that and the benefits are marginal for someone who has a bit of experience behind the wheel. To your point of clearance, the rear axle and shock brackets on the Titan are the best design, by a long stretch. Some say that is why others can provide a car-like ride. I get that, but I have two cars, I need a hunting truck.
2. Stick with some style of 18" tires. Much larger tires again add a lot of complications to long-term durability, unless one makes a lot of other changes.
3. Custom bumper to accommodate a Warn winch. I have this on my current truck and after putting this on, I will never have a hunting truck without it. My current bumper is made by Buck Stop Truckwear. It is a beast.
4. Rocking rear differential if need be, if I were to choose the Tundra.
5. Topper and cargo bracket to on/around topper. My last six trucks have had toppers. Absolutely necessity for the amount of gear we have with us while driving to a location and driving from camp to the trailhead. I have abused and broken so many toppers, I could probably do a lengthy thread just on toppers. I want a cargo bracket that will hold my extra spare tire (I never travel without 2 spares, sometimes 3) and my hi-lift jack. They take up too much space under the topper.
My goal is to get by with nothing more than those after-market upgrades. The list of what a guy could do is lengthy and could cost over $10K if you went full-bore. Not going there.
If I buy an F-150, I will need to do the most upgrades. If I buy a Power Wagon, I will need to do the fewest upgrades.
I am waiting for the Nissan engineers to give me the specs of the new V8 gas models for the Titan that is due out in early to mid-2016. It will not be the beast the new Titan XD is, but I suspect it will have a lot of very useful and practical features. If they have a model that is off-road ready as the current Pro4X model, they will have a winner on their hands for guys looking to use it the way I do.
One consideration that I have not mentioned is price. Right now, of all the rigs I have looked at there are some very big price differences and I am scratching my head as to why the prices are that different. The most expensive of those I am considering is the Ram Power Wagon. The least expensive is the Nissan Titan. The F-150 FX4 and the Tundra TRD Pro are both about the same, depending upon what packages you add to the F-150. The range from highest to lowest is a difference of $12,000. That is a lot of money and had best come with some valuable benefits to justify that price difference.