I would love extra scenes. It's a DVD, you can watch at your own pace. Long ass movies only get annoying to me if they suck or at the theater. The last lord of the rings movie is a good example. Good movie but it had like three endings, fucking ridiculous. How ever watching it at home on DVD was fine, I even liked the extras on and all that stuff.
Also for the amount you pay for these things its only right that they give you something extra and it makes it worth getting a DVD rather than trying to find a "good" torrent.
I feel that the extra content shouldn't pass the point where your head is about to explode.
I haven't even finished watching Revenge of the siths step by step process from art to cgi from casting. It's too much for me.
With that said, a 4 disk set with over 2 years of bonus material isn't my cup of tea which I hear The lord of the rings set is like