As stated, a well balanced TJ will perform well just about anywhere but it may not be optimum for certain types of wheeling (hill climbing, Mud, rutted out clay trails, etc...).
Even if you typically trailer your jeep to parks, don't discount the ability to be able to move at a higher speed (40 mph) along dirt/sand/gravel roads. It makes for a long day when you do go somewhere where you have to get from one side of the mountain/desert to the other and you can only go 25 MPH. When we finished Pritchett's Canyon in Moab, we still had like 20 miles of dirt road to get across to get back to pavement, the dirt road was way worse than the trail!
I love rock garden, rocky ravines, and creek bed type trails. These trails are tight, technical and will result in some body damage. It is also about picking a good line and knowing where your front and rear diff is located. Also, being able to get the front tire to the rock in lieu rock making contact with bumper or fender helps tremendously. So if you want to run these types of trails make sure you have ground clearance all around and that you have body protection (I failed in that category). The mud in the east, southeast also requires you to have tires that work in mud, which may or may not also perform great on rocks (i.e. stickies don't work that great in mud, but work great on rocks).
I am also going to Moab next year and Moab is pretty much wide open (as compared to east coast, yes there is some tight spots and large drop offs but I wouldn't say tight). Moab also has large steps and the break over angle to get over these steps is critical. If you get more extreme, not only breakover angle but also approach and departure angles. So I need to consider that for my jeep since that is what I want to do. As stated above, I need to be able to move from one trail to the other, so I need to be able to run dirt/gravel/sand roads.
I also do 1 or 2 overlanding type trips every year usually in the winter, and these trips are usually 90% trail and there will be mud and chance of snow. So my rig also needs to be able to handle that while also hauling gear. Ability to install top and doors and working heat is a plus!
Never been there, but I imagine that Johnson Valley is a good proven ground because you have to be able to run the desert at higher speed to be able to get to and from trails/camp, there are rock gardens, steps, dusty rocks, and steep climbs. So it captures pretty much everything except maybe mud and trees!
Hopefully a few of us will make a trip down to Hawk Pride this fall, keep an eye open and come down and join us!