Well now that this DLC announcment has hit I can express nothing but the highest levels of schadenfreude for the impatient, self-important beings known as the L4D2 boycotters.
Yes I am calling the boycotters out on this because they have acted in ways which make me ashamed of being a gamer. The people who think they understand how game development works and that somehow they should get things for free if the development time is too fast or a sequel comes out in a timely manner. The people who think companies owe them something for no good reason other than "I bought your game", and think that things like having a working online component and a game that's mostly non-buggy isn't good enough.
Personally I was always going to get L4D2 regardless because
A) I trust Valve. Sure they challenged my "faith" so to speak when the random drops in TF2 started, but they actually fixed a majority of the problems with that within a week and I was pleased. And
I didn't need to join a boycott group to get that result.
B) The boycott group was already lying when some of them said there was no dev kit still. Yes there was. It had been available to anybody for about a month before L4D2 was announced. Sure it was a beta, but it only took about a month and a half after that to be out of beta and "ready" as it were. So to say Valve wasn't delivering on promises was misleading from the get-go. And it's not like they suddenly started speaking the truth either (and no, their version of the truth doesn't count).
C) I've had enough fun with L4D1 to feel I got more than my $50 worth, and thus am perfectly willing to spend $50 on a sequel that expands on the ideas and makes them better.
EDIT:
It's two chapters long and made for versus mode. They hope to fight the problem of ragequitting with a shorter campaign. Considering the number of different teammates I end up with just going through the first level of a normal versus games, I don't have high hopes
I dunno I think this is actually a good idea since, although I've never ragequitted in versus, a versus match will still run very long just because of the nature of it, especially when a 4v4 gets going. So it makes sense even from a non-ragequit stance to have campaigns that are shorter to work in versus. Or even as a warmup for expert if some people aren't that used to that level of difficulty.