Thats the easy way but far from perfect. I put the temp probe on one of my CPU air coolers heatpipes. Its readings fluctuate between 28 and 36 degrees C depending on CPU load. The problem is that when having short bursts of heavy CPU load, there is not enough time to heat the probe up and CPU temperature raises.
If the heat pipe, and the fins aren't hot yet, there's no point in accelerating the fans. It's the same thing with watercooling, just aircooling heats up faster. The fans don't cool your CPU directly, they cool the heatpipes, which cools your CPU. In practice it's the same since they heat up pretty quick.
And if you want the curve to adjust to ambient, you'd need an Aquaero, that can run virtual sensors internally, whereas the Quadro requires the Aquasuite service to do the same thing. but it would still be with temperature sensors, not reading the CPU temp directly.