Right, Carson is the only one who really singles out Molesley, the other servants seem to get along with him. Also, Molesley wasn't introduced as purely pathetic - he was a potential love interest for Anna, who treated his affection for her kindly. Edith's been kicked by her around by her family since day one.

Is there a specific scene in a previous season that shows the origins of why Carson hates Molesley so, so much?
Even though I hate that Edith is always treated with contempt, I somehow find the downstairs treatment of Molesley consistently hilarious.

Anna Maria storms out of practice.
Union Bob: Can you imagine being married to that?
Warren the violinist: I was, for eight years.

Each time I try to think of something to say about this show, I hear the voice of Roger from American Dad:

You may be diverted to learn that his character is the youngest brother of that noted dandy, the Marquess of Hottlointon, who also seeks to win Lady Mary's favors.

Personally, Mary has never been one of my favorite characters. Sibyl, naturally, was my favorite of the sisters when she was alive. Edith gave almost as good as she got in the first series - spreading the tale of Mary's Turkish assignation through society - but since then she's been the saddest of sacks in the…

There's a self-help series called Why Men Love Bitches. Each time a new suitor appears, I think that the title could be far better used in a novelization/faux-memoir:

People are commenting on, and making good points about, the sexism and racism, but so far I haven't seen anyone mention the apparent ageism.

Instead of child actors, they can have a cute little monkey sidekick.

I can see that. Castleroy is led to believe that Greer's been murdered. He takes down his rivals in increasingly elaborate spice-related ways - forcing them to do the cinnamon challenge until their lungs collapse, putting them into a giant pepper grinder, drowning them in a tub of vanilla extract - and becomes an…

"kill Castleroy"

I also liked the scene introducing King Antoine (though it would have been better if he name-dropped his son).

Castleroy, noooo!

To me, the season isn't a complete disappointment, but you make some really good points.

A loose slate needs to fall off the roof and get rid of Leith once and for all.
He's allowed to stick around only if he is abducted and brainwashed by Clarissa.

I was surprised that Claude was still in the castle post-poisoning. I really expected Catherine to just knock her out, and it would cut to a scene of her regaining consciousness on a boat to Corsica or something.

Next Time on Reign

Ahoy, Castleroys!

After reading the interview on EW, I share concerns with others here, but also like others here, am going to try to reserve judgment.
I learned from the comments on that piece that the showrunner also worked on Felicity. The comment was basically something like, "Ugh, this woman wanted to have the character Felicity…

It's possible that he wasn't connected to these particular radicals in this region, but has an overarching agenda. This episode made him seem pretty clueless, though.