The demo for Aliens vs. Predator is out, and it seems to be receiving an overall "meh" sort of reaction. I've been playing it myself, and I can understand where this viewpoint is coming from... there's no real "wow" in the demo. However, I don't think the shortcoming lies necessarily in the game itself, but more in that deathmatch was chosen to showcase the demo.
Of all the versus modes AvP is shipping with, regular free-for-all deathmatch has got to be the weakest, and doesn't play to any of the game's strengths. Who wants to be a marine when you have to worry about getting shot at by other marines, as well as aliens and predators? And aliens should be hunting together, not trying to swipe eachother off the ceiling.
Any other mode, in my opinion, would have provided a better first impression of what AvP multiplayer can offer. Infestation mode, for example. The game starts off with mostly marine players. When an alien kills a marine, the marine turns into an alien. Late in the match, it's a couple of marines fighting to survive against a larger horde of aliens.
Hell, even team deathmatch would have been more enjoyable, so you could at least work together.
I've noticed there is also an issue with connecting to some matches, which probably isn't helping matters. But regardless, I'd suggest not placing your entire judgement on a single versus mode that really doesn't play up the game's strong points.
As someone who was a bit of an AvP2 multiplayer junkie for a little while back in 2001, I definitely recognize some familiar elements in the game. I think the multiplayer has some potential once we have access to a full roster of maps and modes.