...the worst thing is that even though there are some new things, they just don't seem all that great. A grenade launcher, well okay, why not, doesn't change much. A Charger... seems like a reverse Smoker to me, right? Incendiary Ammo is wasted on normal infected (they die in one hit anyway). That other new Special Infected, Spitter or something? Isn't that just a variation of the Boomer?
New campaigns don't cut it, either. If all Valve had done so far is add new maps, we would not even have seen Payload - it's a new gametype.
I'm simply not convinced and am certainly going to wait at least half a year until I'll consider buying L4D2.
Buying L4D early, believing Valve would update it as regularly as they update TF2, was a mistake I'm not inclined to repeat.