Inside Episode 511 Mad Men: The Other Woman - YouTube
Christina Hendricks talks bout how confusing a situation is was for Joan. Toward the end of this clip, she describes the last scene where Joan comes into Roger's office when he calls all the partners in for the Jaguar call. She talks about how Joan feels that the men have all done worse than she did in the course of doing business. But I think it's too complicated to try and justify it that way. She is definitely indispensable to the company, but she isn't in accounts and she isn't in creative. She made partner in a way that none of the men could have, or would have even wanted to. I can't see how that won't negatively affect their attitudes toward her when she tries to assert herself as a partner. (Because they are men, lol)
Either way, it should make for some more great drama.