When I say clearance, I mean actual clearance, under axles. That's where the magic happens ha ha. going from a 285 to a 315 will net you apporx .5" of extra clearance. but a lot more headaches trying to achieve that .5. With independent front ends, you add full lifts there are these gawd awful truss systems and drop brackets hanging down. So, from the side, your truck looks huge, then look at it front on it looks like a tinkertoy set is under your truck. I say, keep er as is now. and wheel the crap out of it!>4WD the clearance issue is always the differential height which tires are the only way to raise that - so you're right - with a 35" tire I would see 1"-1.5" increased clearance from that perspective. A lift would also give me a bit more wiggle room for going through water (and it invading my cab) as well as the improved angles for going over things. We don't rock crawl by any means, but we have been on some trails that had some steps to them.
I am not sold by any means on doing a lift as I see the downsides as well as the upsides. I also know that a 35" tire is a lot more capable offroad than a 33" on a truck my size. A 33" tire on your Jeep would be the equivalent of a 37" tire on my truck with the angles due to the increased wheel base.
Anyway - all advice and input is appreciated as I am thinking this through - you raise a lot of good points and they are appreciated.