33's measure around 31.5" typically. That comes out to 1964 rpm at 60 mph in 4th. Matches perfectly to what you're seeing.
You'd be surprised at the increase of available torque going down to 31's and then also changing gears from 3.07 to 4.10 or 4.56. It's hard to describe especially when it feels normal enough already that you don't think it's "bad", but that all changes once you drive a lower geared setup. You might be able to find someone near you that you could test drive their Jeep and get an idea of the difference.
The main thing I don't like about tall gears like 3.07 is that it handicaps all the gears and prevents them from being usable at the times when you need them to be. Putting around town is not such a big deal, but when you're on the highway, 3.07 makes it difficult to find a good gear for passing. For example, 2nd gear maxes out at 65-70 so you wouldn't use it, 3rd gear is way down at 3300 rpm @70, which is fine itself for passing but won't have much get up and go if you need it. 4th is already a low rpm gear and 5th is practically unusable. It's much easier to use your transmission gearset when the axle gears are low enough to allow the transmission gears to rev up appropriately.
