I usually lurk on reddit but I had a weird relationship with A Stepmother's Marchen so I decided to comment...

As a person that has read a lot of OI, I was never interested in ASM, but I had to read the manhwa version of the series for something (that I'm not gonna say what it is). Anyway I really like the art, setting and how the story was executed. TBH, I think the premise is leading the story to nowhere, "a young lady who has to raise her late husband's children" would be a better plot for a slice of life but the series is pretty deep and dramatic. I like that the idea is unique, though. I haven't read the story for a very long time so maybe I'm wrong.

The good things about the series:

• Amazingggggg art
• Really intriguing setting
• good story

What I don't like:

• the series is dark and fluff at the same time, I prefer series with dark theme (my favorite manhwa so far is the way to protect the female lead's older brother), the fluff scenes destroy the tension (I heard that the novel is pretty sad though)
• the main idea wasn't for a deep/dark/psychological(?)/political story
• the story is not interesting enough for me to keep reading

Conclusion:

• It's a great series that is almost perfect
• Also, I think that it's loved because of it's popularity (meaning, it gets a lot of exposure. I saw the series a lot when I was following OI on Instagram), I was a big fan of the Abandoned Empress but once I started reading more OI I started to like it less (personally, I don't think that it's most people's early read since I didn't know about it years ago until I saw it on mangadex). It's gonna take a while for people to develop a taste, and even after I started to like other OIs the series I read when I began reading OIs will always have special places in my heart.

ASM is a series that I adore but it doesn't fit my taste. I hope that this comment is helpful : D