I concur, the less complicated the better. When this motor goes, I am actually gonna bolt in a Golen stroker block (4.6L) for a Jeep.
That 4.0 is bulletproof and darn near submersible with a snorkel (dont ask me how I know that). And at the same time you can swap in a Jeep transmission and NP231 which are plenty for these trucks and time tested and proven.
I beat the heck out of my TJ and never ever had any trouble with that setup. And they are soooo easy to work on. Yes they kinda suck on gas but they will get you out there and back reliably.
And in another thread is the mention of a Taurus fan swap, and thats a very common swap on Jeeps too. I had a switch rigged up on mine to kill the power for deep water or mud crossings so it didn't burn up the fan motor.