As Bornakk says, the devs love 25 man raids too-- since 40 man raids could be carried by about 25 good players anyway, it makes things much easier for everyone, in terms of individual contributions.
Now, if Kavis is asking to return to the 40 man content, I'm completely down with that. BWL, AQ, and Naxx were fun to go through when you had a good group rolling (as rare as that was), and the content there shouldn't be abandoned (Naxx, we already know, is likely being repurposed in WotLK). But as for a return to the days of trying to get 40 people together for five hours on a Sunday evening? No thanks.