Simpler than an ESC = H-Bridge? No?

I am currently in the process of trying to build an autonomous exploration vehicle based on the Arduino platform. To this end I have been looking for possible motor configurations that would be flexible enough to drive a car both forwards & backwards at various speeds. The best solution I have come across so far however is to use a brushless motor and an ESC circuit, however all the ESCs I have looked at so far seem needlessly complex with endless programmable options (not to mention hard to control using the arduino servo library).

Is there a reason no one seems to uses brushed motors in series with a variable resistor (to change the speed) and h-bridges (to change direction)?

Also, as a side note, can I use any ESC with any brushless motor (provided the recommended max/min current and voltage criteria are fulfilled?)

Is there a reason no one seems to uses brushed motors in series with a variable resistor (to change the speed)

Yes the reason is that it is a very poor way of controlling the speed of a motor, especially at low speed. The power the resistor dissipates is high and if you want a processor (like the arduino but any processor) to control the motor you can't do it this way as there are no high power digital controlled pots.

Also, as a side note, can I use any ESC with any brushless motor (provided the recommended max/min current and voltage criteria are fulfilled?)

No, the method of controlling a brushless motor is different from that of a brushed motor. You need an ESC that is specifically designed to control brushless motors (or can do both types).

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The Quick Shield: breakout all 28 pins to quick-connect terminals