While not a specific commentary about the trailer and more an audio interview, there is a trailer of Kick-Ass online that features Matthew Vaughn's words over the top from a telephone interview, and it's rather interesting to hear him talk about the film.

The comments are short, just enough to cover most of the trailer, but he doesn't refer to the trailer at all. However he does talk about the tone of the film and his intentions for it.

He does point out that he did consider what would happen if someone watched Kick-Ass and then decided to go and make a superhero costume and go out and hit some gangster over the head with a lead pipe. So he made sure that everything is grounded in a hard reality, and when the lead character does that, he gets pretty messed up.

Here's one of Matthew Vaughn's comments from the Kick-Ass trailer with his interview over the top from the French Premiere through FirstShowing:

"It's like what we did with Lock Stock and Snatch, you know, there's a lot of violence in those movies but you laughed through them."

I am looking forward to that, and that's the exact feeling you get from the trailer too. It's a powerful aggressive, no holds barred one, but there's a comic streak running right through it, even through the scenes in the trailers and clips we've seen where he's getting is ass kicked.

Vaughn is very clear, this is a "love letter to Spider-Man" and is about and for the people who love comic books. I think he's just grabbed an entire audience with that one quote there.