My view of Canon is that it shouldn't be every single syllable of every single word ever spoken in the series of movies. If the writers did something in one episode that they feel didn't work, or has been since overtaken by events, they should not hesitate to modify it.
A lot of people have indicated Kirk's apparent inability to drive a car from a TOS episode. Who is to say that he just didn't have trouble with that particular car? I've stalled cars the first time I tried driving them due to unfamiliarity - doesn't mean I don't know how to drive. Or how about - he was so traumatised by his Corvette experience that he never drove again, and hence forgot how to operate a car.
What I'm saying is that Canon has an awful lot to do with how we interpret what we see on screen. One person may see it one way, another may see something else. For me the new Enterprise doesn't break Canon because it's still the same basic shape, for others it does. I guess it all comes down to how flexible an individual is in his own view of Star Trek.
Q - "I'm mortal! What must I do to convince you?"
Worf - "Die."