When I first read about this, I said, "Okay, cool, at least they're making it longer as opposed to rushing it like with WW and cutting out two dungeons."
And then I got to thinking about what they're doing. First is the timeframe.
With this, Twilight Princess is set to compete with not the X360 launch like it was originally, but now with the Playstation 3 launch. Although there's also Halo 3 at this period, the two will not directly connect, as fans of each game will not be swayed by the other, and fans of both games will get them anyway. However, now the Playstation 3, with it's meager launch lineup and 400+ dollar cost (note, my opinion,) is being severely threatened by two big name games. I say good.
Next is it is going to be launched closely to the Revolution. not after, of course, but close. Nintendo has said the Revolution is not only backwards compatible to the Cube, but has similar DVKs to the Cube. Then I remembered when a similar thing happened: at the end of the Gameboy Color's lifetime around when the advance was released, two zelda games, Oracle of Seasons and Oracle of Ages, were released for the GBC, but also had content that was accessable only through the advance.
I predict that Twilight Princess, while not being a Revolution game per se, will be released close to it and will have additional content unlocked by the Revolution.
As for how this changes my fall plans… I'm still getting alot of games anyway, my top games now are just Dragon Quest VIII and Shadow of the Colossus.