Since the question asked us to respond according to the little bit of information we have right now, I will say that, yes, as I see it from the one minute trailer and tidbits of description, it's overpriced as an expansion pack.
So far it looks like a game pack with a full sized world. If it's true that the main focus is only on one or two careers, that just doesn't seem like enough to warrant being an expansion pack. I understand that the fame system can be used with the other careers too, as it should, but there also should most certainly be more that's new in it to "expand" on this overall theme of the game, like Sim bands and new instruments and such. An expansion pack should never feel like it has left gaps to fill with another pack. In the past games, most of the expansions felt like they offered a lot of possibilities, with themes that felt complete and well-rounded. Including a new world does not do enough to fill those gaps when, in the long run, we players are spending hundreds and hundreds of dollars for our game to be complete.
Now that I've answered, I will add that I do think it's too soon to pass full judgement. We haven't seen what the fame system actually does, or what else is included in the pack. We have a whole month to find out what else is being offered. And, even though this particular theme isn't to my liking, I might change my mind on its value.
