Just a thought and i may be far off in my reasoning: as far as 35s are concerned for a 2.5l "expedition" jeep, would the 35s (with their weight and size) increase stress to the engine over long distances-perhaps lose a few points in the efficiency department? I typically think of 35s as a tire you'd want for crawling-theres a lot of meat on that tire-but downsizing to a 32 or 33 wouldnt prevent you from really tackling obstacles you may encounter (esp since you've mentioned ya dont really want to push towards a rock crawling rig) So maybe a smaller (32-33") tire may be better in this case-less weight for the jeep to haul around, less strain on axles, engine, tranny, and enough girth to still crawl over and negotiate obstacles. just an opinion really, feel free to refute it.
Not really a concern when you consider upgrading axles as well. If you're going to stick with stock axles then probably 31's would be better. Since I'm already running a D44, it's not a big deal to run 35's. The only consideration is gearing and for 35's you really want to be 5.38:1 or lower. With 33's you can get by with 4.88's but you really want 5.13's (we're speaking of a 5-speed and not an auto).
The YJ Long that is pictured in the beginning has 31x10.5R15's on the stock 15x6" wheels and I think it looks pretty good. I don't really want to go lower then 33's for a few reasons. One being, I have a SOA up front and SUA rear netting me somewhere in the 4-5" range and a 1.25" body lift. I like the suspension where it is and 33's will work fine with the extra room.
I'm not moving away from rockcrawling but rather not making a dedicated rock crawler. 35's and up are great for rockcrawling but aren't as great for other stuff. Also my current gearing is 4.56:1 which is pretty good for 31's to 33's. (I installed them before there were 4.88's available). I want lower gearing for better street performance though. So I think either 5.13's or 5.38's would be good. Currently the theoretical top speed is 122MPH with 5000RPM's being max. I want to bring that down to around 90MPH. I would need 5.38:1's for that. 5th gear at 3300RPM's would put me around 65MPH which is about right where I'd want it to be. 5.38's would also give me the ability to go back to 35's with a wheel and tire swap so if I wanted a more rock oriented rig, I could go back easily.
Play around with this chart and you're own setup;
http://jeeptech.com/javaAps/gta.html It will give you a better idea of what gearing you really need and what it will feel like between gears.