In all 8 seasons of The Cosby show Sondra was the weakest character on the show almost none of the episodes revolves around her mostly her other siblings 99 percent of the time, i thought that was wrong i wonder why bill cosby never made her such an outstanding and funny character like the other cosby kids were for example Theo and Denise,sondra was also kinda a downer she never smiled or seemed happy to be part of the huxtable family lol.

Maybe Sondra was meant to be different from the others- she is the oldest and thereby, presumably, the most mature. She was also added into the cast later on in the series- she wasn't part of the initial series cast.

She should have been on their more they could have had episodes that just dealt with her and her boyfriend elvin and their dating and marriage life, Cosby must have been to busy to write outstanding episodes for Sondra on TCS.