Splashee

But they kinda end after that. You know? "Amending Fences" develops Moondancer, and then we don't see her anymore. To me, that is kinda an ending to a story, rather than a continuous story of developing a character throughout multiple episodes.

"Perfect Pear" has another issue than just introducing Applejack's parents for a one time event, and that is having a celebrity voice actor, making it almost impossible to continue that story. This is why episodes like "Sounds of Silence" were really good but to never be continued. Also why we never saw an episode with Tempest.

You can see that I want continuation of the story. The problem is of course that you will always reach the end of a story arc at one point with my wishes. But one episode to end a character's development, is not what I want. Duck Tales had both slice of life, and continuous story, so it also captures these aspects the way FIM did.

"Hurricane Fluttershy" was good! That one developed Fluttershy, had a good story, and kept building on her character without taking anything away from her. That one I agree with you, was the right kind of story and character development!

One out of three are terrible odds. 

No, quite good actually. There were so many seasons, and a lot of mixed episode styles, and it was a good mix!

That is why so many can enjoy FIM
And trust me, there will be new members coming here because they found the show much later in life, and they might think differently because some of these episodes and stories are timeless!