Mo Rocca's podcast has a fun look at character changes in sitcoms. Bewitched is covered starting at 16 minutes or so. Lila Garrett, who wrote many scripts for Bewitched, talks about the change from York to Sargent and how it affected the scripts.

After Sargent took over the show writers deliberately moved away from relationship plots between Samantha and Darrin because Sargent "didn't have the same chemistry" with Montgomery. They deliberately focused more on secondary characters (Uncle Arthur, Serena, etc.). She does say that both York and Sargent were good actors, just very different in the role character-wise.

No negativity just a fun look back at the famous Darrin switch.


https://www.mobituaries.com/the-podcast/season-1/sitcom-deaths-and-disappearances/

Lila has a great line about Endora calling her "playfully vicious."

Both York and Sargent were good as Darrins but I liked Dick Sargent more,he was more relaxed and that made the show better, York was always screaming & yelling & out of sorts & looked like he was about to have a heart attack he was so upset at the Witchery, that was very annoying.

The Dynamics of the show as to how the characters such as Darrin, Samantha & Endora etc. interrelated & the Premise of the show was unchanged by the changeover from DY to DS, everything was maintained as it had been with consistency.

Dick Sargent was merely being consistent within the role of Darrin who refused to live a witchcraft controlled life and insisted on a normal life.

He was merely standing up for those beliefs in his behavior towards Samantha and her witchly relatives and friends.

Darrin and Samantha's relationship was just as front and center in the scripts, and the shows premise along those lines never changed with Dick Sargent, it was just less romantic and more loving and affectionate, more married and less honeymoon you might say.

I think Serena, Uncle Arthur and other guest witch characters were used more to make the show more varied and interesting for Elizabeth Montgomery, more fresh so to speak.

I guess I didn't write that clearly above. Listening to Lila Garrett's interview she (as one of the original writers of the show) specifically stated that the writers chose to change the focus away from romantic episodes because EM and Dick Sargent did not have that kind of chemistry. They also chose to make Darrin much less excitable about the magic because Dick Sargent wasn't as funny/comedic in his reactions. They tailored the writing to Dick Sargent's style.

For me, the dynamic of the show changed dramatically between Dicks.

I didn't feel the depth of romantic connection with Sargent that was palpable with York. And York's motivation for Darrin's actions - that he was a highly strung neurotic (like his mother), desperate for normalcy but head-over-heels in love with Samantha (and subliminally drawn to the chaos/drama)
-- really helped sell the show premise. As did York's comic styling.

Sargent's Darrin just seems crabby and unimaginative (a bit snarky and bitter even). He really is the dull Durwood Endora sees. Whereas York's Darrin was much more than Endora gave him credit for.

Also Samantha's characterization evolves into more of a "straight-man". In the beginning she is often complicit and usually amused by her family's actions - she's a bit of a naughty witch (which is very appealing). But by the Sargent years she's kind of a mad mommy, scolding the others (the same happens over the seasons to Andy Taylor/Griffith).

Whichever you prefer, the show dynamics do evolve considerably over the 8 seasons.

And York's motivation for Darrin's actions - that he was a highly strung neurotic (like his mother)

Hilarious! I never thought of that connection before. Very clever idea on Darrin's character.

Dick York mentioned once that his motivation was that Darrin was afraid people would find out about Samantha and he would lose her (which we saw in one dream episode). Of course that was an over the top fear when he yelled at her once for twitching to simply keep pancakes from burning. Sometimes the writers picked silly reasons for him to get upset about.

Bottom line the conflict that existed from The Wiches Councils point of view was between Darrin's insistence that his family live in mortal world context magic free & Endora & the Witch World's insistence that they & particularly Samantha & the children live a magical life in the Witch world.

Now this had to be to create the dramatic tension & conflict that the story-lines were created around.

Without it there would have been no show Bewitched as we know it.
There would have been only a half a season with that premise of magical gratification before the show got stale with everyone getting what they wanted through magic.

To stay true to the premise & to maintain the credibility and integrity of Darrin's character he had to remain consistent in his insistence that their life be magic free.

Although Darrin received no assurance from Samantha's family of no witchcraft, he was simply being consistent in his opposition to witchcraft by whomever, especially if it impacted on the life of him & his family.

It wasn't that he didn't want Samantha's family to not visit but rather that they not impose witchcraft on he, his family & most of all his children in the process.

I always thought it was a mistake to attempt to 'replace' Aunt Clara with Esmeralda. For one thing, Aunt Clara actually LIKED Darren despite his impatience towards her. More importantly, Samantha had a warm bond with Aunt Clara which made her willing to forgive the older woman's mistakes and even go to bat for her against the Witches Council while Samantha herself at best tolerated Esmeralda and herself lost patience with her(and one could imagine she wouldn't have objected to the Witches Council downgrading Esmeralda to a floor lamp).

I always thought it was a mistake to attempt to 'replace' Aunt Clara with Esmeralda.

A friend of mine told me that as a kid he always found Esmeralda creepy and kind of frightening. She was certainly different than Aunt Clara.