Joan has an uphill battle gaining any respect from the partners. After all, they all know how she got her partnership. As far as they're concerned, her only real business skills are as an office manager.
Burt Cooper seems to be more or less on her side (as long as she doesn't cause any rocking of the boat) and you might find Don wishing her well on a good day, but that's about it. All of them--Burt and Don included--basically think of her in terms of someone who should be seen but not heard by the clients.