If Jeff Freilich hadn't left at the end of season 7...
Here's what would have happened, according to an interview with him:
1) Richard (David Selby) wouldn't have appeared until mid-season, so he would have still been presumed dead.
2) Angela would have been pitted against Melissa to get Falcon Crest back, shades of All About Eve.
3) Although he didn't say it specifically, it sounds like Dan and Vicky would have stayed on the show. Eric, probably not.
4) Likewise, with Melissa, Vicky, and Dan still on the show, there would have been no Pilar or the rest of the Ortega family, or Nick Agretti and his son.
5) Rod Taylor (Frank Agretti) would have been a love interest for Angela.
6) During Richard's absence, he would have been working behind the scenes to help Angela regain control of Falcon Crest. He mentioned that Richard would have resumed his affair with Melissa to do that before reconciling with Maggie.
7) The Thirteen would have still been around, but only for the first part of the season before finally being dealt with.
All a moot point, since he left the show, but it was very interesting to read what might have been.