i can understand you not liking the JK's they are extremely overpriced, and one of the things that made me love my jeep is that it is bare bones and rugged...the 4.0l was a great motor minus the gas mileage and i think they should have refined it more than the complete change for the jks
I will always dislike all things Chrysler, Dodge and Plymouth, with the exception of the Prowler (looked kinda cool), Stealth (Mitsubishi), and Viper (not very many Dodge parts). Everything they make is pure crap. Cheap materials, cheap design, cheap manufacturing, makes for a poor excuse of a car. I don't even want to drive near one on the road.
Now that I've made my disclaimer, the 4.0L inline 6 cyl. you mention, may have been one of the better engines that they have produced. I had a friend who drove a Jeep Truck with that engine, and he got 250K miles out of it without major problems. The rest of the thing was a heap. I've heard from many that engine was known to give that level of service. And your right, too bad they didn't refine it, like Chrysler always does, screws up anything that might have had potential.
If it wasn't for Mitsubishi, Chrysler would have gone down the tubes a long time ago. Heck, even buying AMC a long time ago helped them be a hanger on.