Enter Alexis - This is a no-brainer. The entry of Alexis onto the show changed the dynamic and gave the series the drama for which it is known. The first season of Alexis is exciting in that she is known as the first Mrs. Carrington and the writers found a way to keep her on the Carrington estate (through her studio) in order to perpetually torture poor Krystle.
Sammy Jo - Krystle's greedy niece was a nice touch. She is not stupid trailer park trash. She is rather street smart and her sparring with Alexis was excellent. Teaming her with Steven really did not work, but who else is there at the time.
Krystle Thrown From the Horse - There is being a bitch and there is down right evil. Alexis shooting off the gun to purposely scare Krystle's horse is horribly evil, and it will become Alexis's "original" sin throughout the series. There is always the question whether Alexis did so with the intention of causing a miscarriage. It seems very likely that she did.
Nick Toscanni - Nick's vendetta against Blake seemed contrived and pretty much fizzled out until it was revived at the end. Pairing Nick with Krystle worked a little better than pairing him with Fallon. The character just did not seem to work.
Steven's Relationship With Sammy Jo - It is one thing to make Steven heterosexual, it is another to change Steven's very nature until the episode he leaves. Despite his sexuality, Steven was smart and sensitive. That was all tossed aside to pair him with Sammy Jo and to make him want to be a race car driver. What's with that?
Too Many Enemies for Blake - Everyone was gunning for Blake this season - Rashid Ahmed, Nick Toscanni, Cecil Colby/Logan Rhinewood, even Alexis in the end. Cecil turning on Blake was a nice touch but the Rhinewood persona was just strange.