It seems that the last few seasons maybe had to many cast members. I mean the characters who even lived in the Huxtable house weren't in all episodes. I've noticed that in Season 7 Rudy and Pam and missing in quite a few episodes.

Seems like it.

Cousin Pam and her group were completely unnecessary.

Yes, the last two seasons were really "over-crowded". I did like most of the main characters, but yeah...