True. Like BBC's Sherlock Holmes, short, packed, meaningful. (Too unfortunate it was cancelled because of… well, you know.) And the His Dark Materials TV adaptation (though I wish they extended it to 12 episodes instead of 8 per season, so they didn't have to skip some other good parts of the books).
I agree, like The Flash, while I am a big fan of the character, in any of its iterations, CW's The Flash was just too long, and repetitive. The first three seasons were great. After that, meh. I skipped S04 and S05. Then I continued from S06 to the end.
You know, at least in K-drama land, if a writer can do a 6-8 episode series, or 12, personally I think it shows their talent in writing. The director as well for that matter. Because then, it means they know the story they want to tell; and understand full well what are needed and what can be removed.
I'm not saying the other writers don't know how to write a good story. There are 16-episode and 25-episode (and longer) K-drama whose writers did not resort to filler scenes and episodes (especially in the time travel and mystery genres, every scene is a clue and adds to the overall arc). But, I think it is a challenge to write a 12-episode series, much more a 6-8-episode one season series, like Anna.
They have to pack it without losing focus and the impact. They have to combine the talents of the writer, the director, and editing, to capture everything and present it well. Not only that, but they have to build the characters too, in a short span of time, without taking too much air time away from the main plot.
It's like writing a short story. It's hard if you're not a seasoned author/writer, because you tend to add scenes in your story. If you just remove it later, it gets harder to make any sense, you do have to write from the beginning knowing your target is a short story.
I think, and again this is just my logical assumption, it's the same with writing for a 6-8-episode series. So, I have so much respect for writers who can pull it off and give us excellent shows.