Going up hills in 4th at 2500 sounds perfectly reasonable to me.
There are a lot of variations in what a driver likes. Personally, if there is no one behind me, I don't mind scrubbing several MPHs going up a hill for the sake of fuel economy. I always gain them back on the downhill side, and save a few sips of gas in the process.
A lot of folks put larger tires on their Jeeps, leaving the overdrive gear anemic and causing extra downshifting. It's all in what the driver wants. The Jeep comes with a number of transmission gears, so why not use them as you like. That's what you are doing by shifting to 4th on hills. No problems with that.
About the clutch, I don't have an opinion. Mine is an automatic.