Most vehicles do not run above 200 degrees.
Everybody just thinks it's "normal" because they printed 210 in the middle of the temp gauge. That's unusually hot for most vehicles.
Yes, actually they do run over 200 and no, not everybody thinks that. I think it's normal because I've datalogged many OBD-II vehicles over the years and that experience shows me that it's normal to reach temperatures in excess of 200 degrees.
The XJ has a poor cooling system design, that's why there are at least ten million "my XJ is overheating" threads.
I will admit that I haven't read all "ten million" of those threads, but it seems to me that the overheating issues I read about in them are always due to a maintenance issue such as a plugged radiator, worn water pump bearings and disintegrating impellers, bad fan clutch, etc. I don't recall constantly reading about issues that are due to design flaws. The youngest XJs are now 16 years old, so it seems logical to me that there are going to be some around now that have poor cooling due to a lack of maintenance and normal wear.
There are also limitations to any stock system, and Jeep owners tend to modify their vehicles and stress them well beyond the design parameters of the vehicle in every aspect--including cooling. That is why aftermarket parts are available for most systems, including cooling.
Mine usually tends to run pretty cool - right around 195 stat temperature, so anything above 200 starts to worry me.
Mine rarely goes above 195 except at idle with the A/C running...that's in 90 degree NC July. It never goes over 200 when moving at any speed.
Mine runs the same. It hovers around 196 degrees normally, and very slowly rises when sitting at a hot idle. When towing a 2800 lb travel trailer, I will see it go up to 205 or so waiting for a stop light.
That seems like perfectly normal operation to me, and great performance from a vehicle that has, in your words, such a "poor cooling system design".
Some people seem to think that a vehicle with a 195 degree t-stat should run at that temperature all the time, which is ridiculous. A thermostat works to control a minimum operating temperature, not a maximum one.
Higher coolant temps also make your trans run hotter if you are still using the in tank cooler
The cold side of my radiator, where the tranmission heat exchanger is, shows temperatures around 170-175 degrees at operating temperature. That is normal temperature for an automatic transmission. At the output oil line, the AW4 frequently gets above 200 degrees, so a 175 degree heat exchanger is still doing its job to cool the fluid.