I'm wondering exactly the same thing. I don't want to pay an extra $5 for a blooper reel and 20 minutes of behind-the-scenes footage. The extras on the special edition Narnia DVD were pretty decent; I hope they give us something good this time too.
I don't think there's any reason to worry about the quality (and quantity) of the special features in the Narnia DVD. I went into the amazon page with the expectation that they would have shown the list, but no. Anyway, here's the list of the special features (with the running time listed) and easter egg available on the 3-disc special, taken from NarniaWeb 04:34 - Becoming Trumpkin 10:38 - Warwick Davis: The Man Behind Nikabrik 22:37 - Set of Narnia: A Classic Comes to Life 22:17 - Big Movie Comes to a Small Town 33:15 - Inside Narnia: The Adventure Returns 01:13 - Toastie: More than Just a Movie? 06:24 - Secrets of the Duel 09:39 - Previsualising Narnia 04:31 - The Magical World of Narnia 02:56 - The Bloopers of Narnia 10:15 - Deleted scenes with intros
The list also includes the hidden Easter Egges we'll have to look for:
02:17 - Skandar Keynes: Blonde Cam 00:49 - Sibling Rivalry 01:44 - KC 1st Assistant Director 00:58 - Monster Cam 07:21 - Shane Rangi Also, there's the audio commentary from disc 1 (which I found extremely entertaining in LWW) disc 3 is called DisneyFile Digital Copy, which is just another copy of the movie that's designed for u to watch it on computer and (I think) to capture image