I'm neutral on the whole Twilight fandom and anti-fandom disaster that's filled the Internet for so long.
Really, guys. Let me tell you what I think.
Fans: you're welcome to like it, but please don't start on whether it's "better" than anything else. Films and books don't work that way. "Better" is an objective value that cannot be applied to art. Besides which, Twilight is hardly high art. It's pulp romance, Hell, basically it's a Mills & Boon novella in a strangely optimistic fantasy horror universe.
Anti-fans: you're making it worse. As the proverb goes, "any publicity is good publicity". If you seriously dislike Twilight, stop adding to the franchise's popularity by making your little sisters want to like it because the adult/older world thinks that it's terrible. Stop making blog posts about how much you hate it - all that does is make the world think it's better (speaking as a web designer here, I would not be surprised if more Google hits means more sales, even if you write about how bad something is rather than its qualities). Also, it's immature to hate something so much. Scratch that, it's immature to hate in general.
With those thoughts out of the way, yes, Star Wars was pulp fiction too, and while its simple story had a great deal of archetypal power and its special effects impact on Hollywood leading into the future was enormous, simplicity is a curse, not just a blessing. It was not a high art movie, and it was not anything new or different as far as brilliance goes. It followed a typical "hero's journey" template, with the only inventiveness going into the science fiction world that was built around that plot by Lucas. In fact, Lucas made some better films in his time before that big hit.
I think it's more likely that Mr Kermode has this opinion because he really, really dislikes Star Wars (to the point of irrational emotional impressions interfering with objective comparisons), because he grew up with much darker sci-fi and finds it an "infantalisation" of the films he grew up with:
http://www.guardian.co.uk/film/2007/mar/25/sciencefictionspecial.features
Twilight is much more different from what he grew up with, so he has no attachment that makes him leap out and bite it. So he thinks it's better. Though, one must question how brilliant he is as a film critic if his past effects his ideas so intensely.