I would have to disagree with you there Jack. I have watched various motosports, and most of the time, the new guys use the same thing as the old guys just because that is the way it has always been done, and I believe partially for looks. One day, a new guy shows up and stirs things up with a new design. Take a look at Monster trucks. They race and freestyle. Two totally different applications and almost all have the same "tractor" type mud tire. A few years ago a guy came on the scene with an AT type tread. He was a self sponsored truck. Blew them away in racing, and performed great in freestyle. Unfortunately, he broke some major parts and the truck disappeared for awhile, the cost of private ownership vs. corporate sponsor, once good jump and roll could cost you $50K.
I do think mud tires are great for the trail, certainly not for everyday driving, but AT tires will get you just about everywhere. As Riffraff said, a jack of all trades, but not really great at any one medium.
And Billy, I think you are exactly right about the tires at Moab. That buggy wouldn't look so cool with ATs. A huge disadvantage of the General AT2s: they are soft!! I was rotating the tires on the weekend, lots of gouges in them, and I just went and compared to my Procomps, which feel like rocks and do not feel soft at all. So that 44lbs a tire came at a sacrifice, but for daily driving, well worth it, hence my hunt to get some trail tires.
As for the bumper, I took some angle iron out last night, may weld it across the top and build little "towers" to weld it to on the outside. That would give me a point to stand on and keep the sheet metal in shape. Dunno yet.