OK, to be perfectly honest, the stretch goals do look a bit uninspired.
New race/class does not really mean much without context. If there are only few races/classes in the game, this might be exciting. However, if it turns out to be a race/class very few people want to play, it won't be, so we have to put this down as "potentially more options".
The story grows, a new faction, player housing -- yeah, same thing: more contents, more options.
But realistically: Isn't this what you would expect? Isn't that what you would want? More contents? More options?
Localisation and Mac/Linux versions only mean something for a specific subset of backers. More contents is the only thing that will benefit all players. So I'd be quite happy with 2.5 million = more contents, 3.0 million = more contents, even if it does sound boring.