Characters who came and went .....

[Pammy P]

...... then the show when off piste!

For me it was:

Pamela Barnes Ewing
Ray Krebbs
Donna McCullum Culver Krebbs

All 3 were integral part of the show .... supporting cast members - Katherine Wentworth without a doubt should have stayed longer; along with Rebecca Wentworth for me they were not long enough in the show, characters had so much more to give.

 

[Jock Ewing Fan]

I always thought it was a mistake to write Digger out so early in the series.
There could have been multiple stories that included him,
especially when Rebecca was cast