From the get-go, the oldest son didn't even live under the same roof. They had to make an effort to keep writing him into the show.
More family reunions please.
I believe there were 3 different Abbys on this show. One for the pilot, then Betty Buckley for most of the run. That did it for me. As soon as Jeremy showed up. The show was always addictively annoying what with all the self-righteous sisters, but as people grew up and David was almost gone and Mary wasn't around as much and Tommy was hanging out with Ernie, they seemed to need someone for Nicholas to hang out with.