Uhmmm.... I kinda like it...
Instead of two bars, have just one , where the "0 value" is in the middle, and negative numbers are represented by ice flocks, and positive by fire icons
I dont honestly yhink you should be set on fire because of excessive temperature, lose health instead.
The termal regulator with a Area effect is a must, one can (maybe with an overclocker?) increase the area effect (this machines would get the temperature as close to 0 value as possible.
Also, caves should make you cooler, except when you get near to bedrock, to simulate the earth core temperature.
BUT off course, this must be in the config avaliable to turn off.