Yeah, I kind of agree with you. Hell, the freaking demo for L4D had everything that the game had to offer, except for all the maps. But I'll probably get it anyways. I mean come on, it has a guy who dresses in all white like me. I can't pass that up.
And also, you can't really beat it, just the campaigns. That's one thing that annoyed the heck out of me. No story line.
I still loved it though.. Killing zombies is in my blood it seems. And with the software out to build custom maps and such, people will have plenty out to keep us all entertained soon enough.
And Dual, I agree. It should have been an expansion. But then how would they make their money?