Some quick vs modes.
The biggest problem with L4D at the moment is how long it takes to play 5 campaign levels.
Need something around 20 minute ~ 30 minute length.
Q F T!
My L4D mates don't start until late (> 11pm) so it's often 1-2am before we finish a full game (after all the ****ing about in a lobby trying to find a decent server)
anti-rage quit mode... exactly the same as versus but if steam detects you quit a server in a nerd fuelled rage it bans your account and deletes all your games.
Get a grip.
You want people to ask for permission to leave your game? What happens if they crash? What happens if they have a r/l interruption? What happens if they just happen to be losing but are annoyed at having to play against complete arrogant tools? What happens if somebody is at the door, or the phone rings?
You have absolutely way of knowing why somebody might quit a game, and even if you did, why on earth would you want to force people to play against their will.
Even if you were stupid enough to bring such a system in, the antidote to it is simple; you merely leave yourself logged in, but do nothing. You'd get slaughtered as a survivor inside a couple of minutes, thus ruining to experience for your team. So they would 'quit' (i.e. just leave their player in the server but do nothing as well) so the wining team would lose all credible opposition. So the server would end up being full of players who did nothing just waiting for the opportunity to leave a server without a penalty.
Apart from being rather arrogant, your suggestion is also on the moronic side.
Yeah i like this, your team of 4 has to defend a small house, could even increase the scale to a number of teams defending a small village town or fort.
Defending a small house sounds suspiciously like Survival mode - or were you envisioning something different?. A larger force defending a whole settlement sounds promising. I would suggest a fairly defendable location though, with plenty of ammo, but a larger horde. Perhaps a wide outer perimeter, with a smaller inner perimeter, and a central core - so players can fall back as they need to. Perhaps with key rooms/buildings to defend.
I also like the idea of the TFC/Hunted Map where you have to defend a VIP. You could give the VIP melee weapons and some other skills (explosives, hacking or lockpicking) so that they have an active role as well but are distinct from the other 'normal' combatants.