There is nothing that a trail rated patriot can do that a non trail rated patriot can't do. The low range could give an advantage in certain circumstances that a patriot shouldn't be in anyhow, but just an advantage. The other models are just as capable.
I'm going to reply to your post in a nice polite way, in no way am I trying to doubt the abilities of FDI MK's I encourage more people to take their FDI's offroad. I also will say FDII MK"s are not the greatest thing since sliced bread but there are differences.
The flexing videos I have posted, that can't be done without FDII BLD's I even have a video of trying the FDI mode to go over the obstacle but it would not go over because the BLD's don't activate long and strong enough to get any meaningful torque transfer.
The FDII BLD's will lock a spinning wheel in the air and hold it there until there is movement on the other wheel, sometimes this works, sometimes it doesn't I have proven this many times.
At 22 seconds i'm about 1/2 throttle, 28 seconds I go full throttle and hold it, still not enough force being applied to the spinning wheels. You can tell when I go into the FDII Low range mode.
How does this relate offroad, quite simply if you have articulation and the wheels on the ground don't receive enough torque because the wheels in the air are not having enough brake force applied, you aren't going to move. Now if you are on a surface where you aren't going to have any articulation then this isn't really that big of a deal, but it still matters.
You will notice a difference climbing hills with a FDII vs FDI, the low range absolutely makes a large difference, if you go up a steep hill chances are you are going to lose traction on 1 front and 1 rear tire, when the wheels spin, since the FDI doesn't have aggressive enough BLD's you will just sit there and spin, or slide back down the hill, the FDII low range allows the more aggressive BLD's to function and get the vehicle moving again, Video showing what i'm talking about:
As you can see, when I wasn't in the FDII mode all I did was spin (which is what a FDI would do) When I go into the FDII mode I don't have enough torque to power the wheels that need it, and I had my foot to the floor for the whole time. Part of the problems on my old pat was the 40lb tires I had, they really sucked the power out of the engine. Once again FDII was able to tackle the obstacle.
So even with little articulation when traction is lost by the tires the BLD's kick in and save the day.
Here is another hill climb video where the FDI mode would not have climbed up it at all.
Here is a small hill climb:
I start off in D and 4x4 locked which is exactly how a FDI would behave (ignoring my different overall ratio of 8:1) You can see I had my foot right to the floor but not enough power transferred to the other wheels spinning. At 17 seconds I go into L 4x4 locked (FDII mode) and I can't remember for sure but I think I cycled out of FDII mode quickly to get some wheel spin up before having the aggressive BLD kick in. As you can see in this case even the FDII couldn't transfer enough usable torque to the tires with traction. Solved that problem by going with a bit more momentum and slightly different line.
Yes you could argue that the Compass (or Patriot) doesn't belong in these situations, however in reality it does these vehicles are very capable and more so than most people give them credit for.
So you can't add hIll decent to a FDI but that's really not a point to argue as it doesn't really change the capability. You can lift a FDI you can add skid plates tow hooks all that. Those mods absolutely add more capability.
The fact of the matter is that MK's have open diffs and limited articulation which ultimately limits their performance offroad in many situations. Momentum helps a lot, in a FDI you will have to tackle obstacles at a higher speed vs the FDII, the FDII allows you to crawl along in a more controlled manner. In my FDII I sometimes find I need more momentum to get through an obstacle. (as the video above shows)
The FDII's application of aggressive BLD and low range is what will send it farther down a trail and higher up a hill than a FDI, its just reality.
Here is a video from a member that used to post on here FDI, looks like he has Yokohama Geolander AT/S tires
He gets through the snow alright but it is a struggle at times, in no way am I suggesting that I would have been able to walk through that like nothing everything offroad situation is different.
Here is a better video, showing the BLD is some more challenging situations.
As you can see in this case it works but it takes a lot of wheelspin before they kick in and then it just gets over the obstacle (in this case)
It does illustrate though how the BLD functions on the FDI, and you can see it works, but it is really not as aggressive.
I don't look down upon FDI Mk's but if someone wanted to go offroad in semi challenging environment the FDII is the model to choose IF you had to choose only an MK, if you wanted a more offroad vehicle, there are others.
I have gone to great lengths to test out the 4x4 AWD system on both of my Mk's and taken my compass through some pretty decent offroad obstacles, many of which people thought I was nuts to even try.
I welcome you and others to prove me wrong and take some videos of FDI MK's offroad.
Once again I say this with the utmost respect as i'm not trying to start a flame war or anything. I'm just going on facts.