Well I must say that Nick Gillard hasn't got authority for anything when he is talking about their power level, he is not a source at all, it is his opinion.
And what EU authors say is there opinion, too. Gillard has at least as much authority for talking about the character's lightsaber skills as any EU author does since he is in charge of training them, why wouldn't his word have any credibility?
And the fight on the Invisible hand was going to be very long, they just cut out most of the part. In the novelisation it is much longer...
In the novelisation Kit gets hit head cut off...