Kit - CAS or BB items.
Stuff Pack - CAS and BB items and gameplay items which offer new gameplay.
Game Pack - CAS, BB items, gameplay items and the pack offers new gameplay.
Expansion Pack - CAS, BB tiems, gameplay items and the pack offers a lot of new gameplay, the pack often comes with a world.
I'm not sure if the new horses expansion pack could have been a game pack, it's difficult to tell from just looking at the trailers, it depends how well the pack plays...
I don't think customers should feel the effect of what budget they had so if horses were difficult to make, the publisher should instead raise their budget so that their customers get what they expect and that they are happy with the pack. You should not get customers to discuss if the pack is an expansion pack or not, game development is difficult and some things are going to be more difficult to make than others so some packs are simply going to cost more and the customer should not feel the effect of that.
