I'd gamble it has more to do with the fact you have to overcome the resistance of 2 extra axles and mechanical differentials of the AWD forester that is making it appear to be a bit more difficult than the lazy v8 2WD Cobra.

With that said, check out where the engagement of your clutch is. I've had people complain about grabby clutches(stalling) only to find out the engagement point is almost at the top of the throw (Former Subaru tech)