I am sure Sky would do a good job like they have with the F1 but it is not ideal to have it on a pay channel, especially if it is on the F1 or Sports channels as these cost even more than a basic Sky subscription. I remember when WRC was on ESPN the viewing figures were really dreadful.
Maybe Sky could rebrand "Sky F1 HD" as "Sky Motorsport" though and then WRC would have a good synergy.