Hello everyone.
So I've played the vanilla version of Arkham Horror a few times with my friends now (although not nearly with as good interval as might have been needed because every time we've needed to re-familiarize ourselves with the play setup and the rules and such, but what the hell, it's a big game).
It's time to take it to the next level, and im eyeing some of the expansions for AH. However, I want to get something in particular as the first expansion, namely something that really ramps up the game difficulty.
So far we have never "lost" the game, nor have we ever experienced that the Ancient One awakens (though it has been close a couple of times), and I have to admit that Yog-Sothoth could be quite a b*tch due to his insatiable appetite for investigators that become lost in time and space, but to be frank I find the game to be a little too "easy".
So I'd like an expansion that adds some serious difficulty to the game and that puts more emphasis on cooperation between the investigators to win. Because so far we've managed to beat the game every time and most of the time we're not planning or cooperating at all, just running around the board and running our own race (gathering money, trying to find cool weapons and magic items, beating monsters etc. etc.). It seems to be going against the mood of the game when you can basically ignore cooperation altogether and still win without even being close to let the ancient one to awaken.
So which expansion would be best to get if you want to add more difficulty to the game? While I am sort of tempted to get one that use an entirely new board (I have a particular eye for the Innsmouth expansion), I'd prefer if I could get just one of the smaller expansions first and still achieve the desired effect (i.e start to expand the game in baby steps).
So if you could break it down for me, and present some pro's and con's of certain expansions (including stuff like how ardous certain expansions are to use when it comes to flicking through the rules and setting it all up as well as game play aspects) it would be very helpful.
Cheers everyone. 
//VT