They get rid of the good ones way to early.

Ysayle, Yotsuyu, Emet Selch...

And then we have the other ones, that should be explored because they could have great storylines or were set up to be great characters, but SE just kills em or ignores them

Ilberd, Regula van Hydrus, Runar, Magnus, Ran'jit, Blue/Red Jongleurs...

And the annoying, face palmy cringy ones overstay their welcome

Zenos, Lolorito, Zenos, Omega, Zenos, Alphinaud, Zenos, Crystal Exarch, Zenos…
Frankly Ishtola could be on this list too, she is just so holier than thou that she has become more of an annoyance than anything.

SE has a thing for cringy, emo villains with big swords tho so its no surprise they kept Zenos alive. He is just such a flat, one dimensional character that feels like he jumped out of the pages of some bad tween fanfic.

Emet Selch especially was so well written and given such a personality in the short time he was part of the cast that he feels like he's been a part of the story the whole time. He literally felt like an old friend. Which is no small feat in the world of writing.