you are obviously within your rights in not buying any ES game, but if your sole reason for doing so is because you don't want to play American Indians, I'd like to point out that the expansion pack actually offers a TON of new stuff for the European civs.
1) they get new units, new mercs, and new technologies not available to the natives.
2) they get a new building not available to the natives.
3) they get 25 new cards each, many, if not most, unique to their civ. Example: the Spanish card "Mayan Allies" that lets them muster Holcan Spearmen.
4) they get a new potentially game-winning power, "Revolution" which is, again, not available to the natives.
Plus there are new maps, new minor native allies, a new way to win the game (Trade Monopoly) etc.
The WarChiefs offers heaps of stuff to European players who never want to be a native civ.