I recently gave up on L4D because Valve has broken the ability to play Versus mode on advanced difficulty
IIRC, wasn't that changed while the game was still in beta? Personally, I think that it's better this way anyway, because in Versus mode the main challenge is supposed to be the Special Infected (controlled by players) anyway, not the Horde. If you want a tougher Versus game, a tight-knit team of opponents should suffice.
They brought Advanced Versus back after they broke it the first time, it broke most recently with the update that gave us Survival mode. It's not just the quantity of commons, but increased damage from everything, including FF and fire, that made it more challenging.
Melee cooldown also pissed me off quite a bit, it's gotta be off for Advanced.
It makes it so you can't just melee-spam your way through a mob of horde. As a player I agree it's annoying, but it's annoying in the same way that being out of breath while you're running is annoying. I can see why they did it; it makes it so you have to shoot your way through a mob, or even better for the Teamplay aspect of the game, get teammates to kill the Horde that's mobbing you at the moment.
Agreed, for normal difficulty, which is all valve seems to care about.
And while I'm ranting, the lobby system sucks.
It doesn't work perfectly, but I can see why they wanted it that way; you can either join a random game with random strangers, or you can find a group of friends to play with. Left 4 Dead isn't the type of game where you want a traditional game-server model, which is best for Deathmatch and CTF, or similar styles derived from those. Instead, you want everyone to start at the same time, like in an RTS. A lobby is the best model for that.
I like the idea, but it's really really buggy.
Happiness is twin floppies.