The AW4 has a great rep but swapping to it is not that easy, esp on the 96-98s with OBDII, your older OBDI ZJ it might be easier, but you would most likely have to get the wiring and etc from an XJ of the same year as your ZJ to work. The other option is to rebuild the 42RE with better aftermarket parts, which would be just fine. They can be built very strong with some widely available aftermarket parts.
I'd get the 42RE rebuilt at a shop that builds racing transmissions or heavy duty truck transmissions. The good parts are out there. Keep in mind that the 42RE was based on a 904 style Chrysler Torqueflite which in its day was one of the best transmissions out there the rep suffered because of poor quality of some of the parts and updates (converter clutch and OD) that were not that well done.