Well, we now know that NPCs will be making appearances in this game, who guys expect to see? Who do you want to see? What roles to you expect them to play?

I personally expect to see at least two more members of the Bat-Family, Robin or Nightwing and Oracle. If it's Tim, I expect some misfortune to befall him early in the game, taking him out of the picture (to explain why he isn't playable). If it's Dick, I expect him to encounter Bruce at some point, exchange some words, then go off to deal with things his way, by himself. I think Oracle is going to get to play a pretty big role in the game, coordinating the DC heroes and such.

On the subject of Nightwing, maybe we could get a cameo of the Outsiders (you know, if there's a huge fight or something they could appear in the background fighting Tarkatan hordes or something).

It'd also be nice to see Huntress.

I'm also thinking we will DEFINITELY see Jimmy Olson and Louis Lane.

Since he is my ABSOLUTE FAVORITE hero, I would love to see the Question (Vic Sage) doing something.

I'd expect to see other members of the GLC as NPCs, definitely John and Killowog, probably Guy and Kyle as well. I'd give anything that isn't vital to living or enjoying video games for Alan Scott to appear.

I'd also like to see Jay Garrick and Bart Allen, especially Jay (what can I say, I love the Golden Age heroes that are still around).

on the MK side:

Certainly Kung Lao. Baraka for the simple fact that Tarkatan hordes make great canon fodder enemies. Stryker would be great for a cameo. Not Hsu Hao, the world's worst MK character. However, for the most part, I'm not too keen on MK character cameos. Either the characters are too major to be cameos because you'd rather be playing them, or too minor and you wouldn't really care.