As much as I love when obscure comedians (Amir Blumenfeld and Bobby Lee in this case) get roles in movies like this, I find it usually doesn't turn out as great as it should. Year One being a prime example. But at the same time, bonking Neil Patrick Harris mannnnnn
And don't worry about the 3D. In only two cases does a movie become protected from the "ugh another 3D movie" syndrome. If it's the third film in a series (making it a throwback to Jaws 3D, and a sort of parody), and if it's a comedy (meaning it's going to be over the top, and in no way serious).
Or if it's an animation.
Or if it was actually made with 3D cameras.
Not sure about this being a Christmas special, though. Christmas specials are normally made with kids in mind, and this is clearly not going to be a kids movie. The only reason I can see them doing this is so Comedy Central will have something to play during the holidays other than Bad Santa (don't know why they never play National Lampoon's Christmas Vacation, but whatever), hoping to get them guaranteed tv royalties.