I don't think she is going to do that with this tour. She said in an interview that she wanted to do a small venue tour so it could be more intimate. The Utada United DVD certainly wasn't a small venue, and the stage was state of the art.
Not that I'm against her doing that, I just think it would take away from the experience if she wanted an "intimate" feel to the tour and then mass produce a dvd from it. That's just me though.
The other argument would be that she and her fans loved the tour so much that she made a dvd to give the fans a memento. I'd buy it regardless.