[Mister Ed]

The problem with playing with 8-players is one that can't, in my opinion, be fixed by adding more cards.

The problem is that the game takes FOREVER (in my experience, which I admit is limited to a couple of examples- but the principles seem sound), because:

1.) Every round has to go through 8 people, some of whom are bound to want to think about what to do at some point. It can be rather dull waiting half an hour or more for your turn to come around again.

2.) With 8 people, there are so many cards out there to mess with people that it becomes kind of difficult to get a winner. Toward the end of the game, if you are going for the winning level, there is a decent chance that, among the SEVEN people trying to stop you, there is sufficient means to do so. You end up having to wait for a BUNCH of people to be shooting for that winning level at the same time before anybody has much chance of getting it.

So adding more cards can help in the sense that you won't go through the decks as fast, but it doesn't really address the problems that I see with playing the game with that many people.

As to the question of how you add expansions, yeah, they are designed to just add the whole thing in. You CAN (and I do, often) decide to add some expansions and not others. That's fine. As long as you have the Core set, you can add whatever combination of expansions suits your fancy, though they are designed to be added in order, so if you skip over one, you will likely have a few cards in the later ones that refer to something in the one you skipped. Some people would pull cards out to address that oddity, but I usually don't bother. There are enough things in the game that you pay for with discards that I don't find it too worrisome to have the odd card that isn't too useful.