The thermostat controls temperature. The OEM radiator is capable of cooling to well below 210°; the thermostat keeps that from happening because the ideal temperature is 210°. Cooler isn't necessarily better. Your engine and its' systems are built to a very specific design to optimize fuel efficiency, life of the engine, etc.. It expects to ramp in temperature at a certain rate and for the radiator to cool at a certain rate with the thermostat controlling it to the optimum temperature. It isn't going to perform any better because you install a radiator that "cools better".
'06 Jeep Wrangler, 65th Edition, stock.
'98 Jeep Wrangler, stock.