Lo, Med, and Hi are a rough guide to the level of heating for that particular element. My three element stove shows it in Watts. The largest element is rated 200 to 2000 and the smallest is from 130 to 1500, the middle one is rated 120 to 1200. I don't think that a temperature gauge would be appropriate though. Can you imagine wanting to cook some bacon and setting the temperature to 250(480F)? Or boiling some water and setting it to 300(570F)? Don't get me wrong though, If I did a lot of stove-top deep frying or candy making(needs good temp control) I would love to have one with a temperature gauge.

An oven uses a thermostat that actually senses the temperature of the air in the oven and turns the heat on and off to keep it where the knob is set. A stove can't easily measure the temperature inside the pot, only the heating element. The temperature in the pot is not necessarily proportional to the temperature of the heating element. It depends on the size of the pot, what's in the pot, and whether the pot is covered.