The 4.0 comes from the factory with the 195 degree thermostat. This is the correct thermostat for most stock 4.0 applications.
The engine coolant temperature (which is what you're reading on your dash) is usually between 200-210.
Just because you have a 195 degree thermostat doesn't mean that the engine will run at 195. The thermostat does NOT control the maximum operating temperature of the engine, rather it is the approximate temperature where the thermostat "opens".
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!