What are you planning on going to? I'm not sure what you had before...
I had 285/70/17 last year. They're basically 33x11x17ish. I've been talking with Toyo about buying them back. It's mostly been an issue on my end of not having time to go spend a day at the tire shop. I've been through 7 tires total now - and still have 2 that won't balance. One was 16 ounces out of balance and they couldn't balance it with weights close enough to get below about 2 ounces out of balance - which is still quite a bit out of balance. Toyo and discount tire have been good about trying to fix it. For whatever reason the AT 2's are problematic in that size.
I have another set of wheels and tires i use for daily driver duty. So it hasn't made it very high on my priority list yet.
So if I can swap them out to something else - I'm going to go for 285/75/17's. They're about 1 inch taller. Not a ton - but would probably help a bit.
I don't think tire size held me back very much last year. It was mostly an issue of belly and body clearance. The breakover angle was a consistent problem. I live in Utah so I try to keep the COG as low as possible because I spend most of my time around Moab. That's not ideal for the Rubicon. I have adjustable coilovers up front, so I'll set them an inch or two higher this year. I was way overweight last year so my 2.5ish lift was more like 1.5 inch at full weight. I'm going to run lighter.
For rear suspension I'm not totally sure yet. Last year i had stock coils in the back with 1.5" spacers and airbags. I'm currently using Dobinsons 2" coils for KDSS with no spacers - and I'll probably just use those plus the spacers for Rubithon depending on weight.
The goal is to be at a true 3" lift fully loaded. That would be around 2" higher than I was last year. I think that small change will make a huge difference. A lot more than tire size.
I would also say that you absolutely need full skids including the fuel tank, and some good sliders. If you don't have them - bumpout sliders are probably a good idea.
I used them a lot.
I'm probably going to change the outer hoop on mine to add a bumpout. Protecting the rear quarter panels was where I has most of my issues. I also have a rear bumper skid that got a good workout. The OEM bumper cover will get hammered.
Finally, as odd as it may be - I may install a pair of wheel spacers at camp the night before in the rear only. The front is an issue with steering that they cause rub problems due to the scrub radius. But having the rear tires another inch or 1.5 inches offset will offer a lot of protection to the rear fenders. That's where I had the most risk of damage and is the hardest to protect. I didn't actually damage them - just some minor scratches where I barely touched the plastic of the fender flares. But the risk is high. - like really high - and I was often just lucky. So bumpout sliders and slightly wider tires are probably going to be the best defense against that damage. Unfortunately that's the most expensive panel to fix. Doors and front fenders are pretty cheap to replace if you happen to damage one. The rear quarter panel is the only one that you have to cut out to fix.
Hope that helps. It's harder than I had anticipated, but do-able in 5th gen with a good spotter and careful driving.