I ran my 1717 for awhile, but wanted to use that for another project.
Since, I've installed a CC1520 in place (which is pretty close to the stock motor's dimensions but 1600kv instead of 980kv). Interesting enough, my 1717 ran warmer (although never hot) than the 1520.
My guess is WOT (wide open er.. um.. "throttle"). Brushless motors in general under no load or loaded don't like to be run full bore for extended periods of time. My 1717s have always had brutal power and low-end torque to throw around my converted Muggy and LST XXL with ease. Top speed I rarely cared about as the vehicles have a relatively high center of gravity and would topple over hundreds of yards away knowing my luck.
With this car, one is more inclined to dart around like a land missile. So I think perhaps your driving style has a hand in things warming up.
To counter this, get a motor that can move the car around proper, but has room to spare in the speed department. Stock pinion with the 1520 on 6s is way proper man. After dumping my 5800 mah packs I'm lookin at 140f, and I live in South Florida!
Ah, one more thing.. the CC blower is neat looking and all that.. but not quite as effective as the blue heatsink/fan combo I referenced earlier.