I think if you basing your opinion of the Nitto Trails on their performance in the mud your not giving them a far shake. Based on you menching the mud is worse where you live now. The Terras are worse AT I have ran in the mud the Trails have to be better.
A buddy and I where using our trucks to move trailers around a muddy job site in the rain. I had Terras and he had Wild Peaks and he almost was out there as long as me before both of us get stuck. His truck is only a 2wd though both CCSBs his was a cummins also so a bit heavier.
IMO Toyo and Nitto are the same tire for the most part. I bet the Toyos are a hair better generally speaking, but in the mud it would be a draw pretty much.
I'd have to disagree with you on the mud part. The Toyo has a better tread pattern than the Trail grappler does to perform in the mud. The trail grappler is rated to do well in the mud, but it did not to my experience. I didn't try it once but multiple times in different conditions. The worst was when my bro got stuck in his jeep with his BFG MT, he didn't have the clearance to go through at that time. However I have TWICE the clearance he does and got stuck easily than he did due to the tires slipping like it was on ice and the tire did not clean out the mud at all. That was in my own backyard woods during the spring, I had a mud king tire in my old K1500 and never got stuck all season before I moved to AZ and got my duramax. I know what an all around tire should be like, the trail grappler was similar but the patterns were too close to each other. I'd say the trail grappler is only good for hard to medium surface where it isn't too muddy.
The terra grappler I had when I originally bought my truck did pretty well in the west coast was because the mud isn't thick as MA is and it is all sand. I got 45k miles out of that tire. However the life span would have been much shorter if I did tow, terra grapplers are very soft and would wear quick during towing. I won't buy the terra grappler out here, my friend has gotten stuck in his own driveway with those tires in the snow. They don't perform well in the snow, the BFG AT KO doesn't either. They are horrible in the snow.
Comparing to my trail grappler to my friend's Toyo MT, I can tell the Toyo will perform better all around due to a harder compound for longevity and better contact pattern for mud and slick conditions.