I wouldn’t call Thrall well developed. He was well developed, he was going to lead the Orcs down a new path … then he was turned into Mr Do-Nothing in Cata.
We should off Jaina too while we are at it. They took a character that was relatively well like and twisted her into what she is today during Cata.
Kind of a self own frankly, destroyed two popular characters in one fell swoop and then not have the talent to create new ones with similar popularity.
Now WoW is mostly filled with characters no one gives a rat’s bottom about. Even if Blizzard somehow accidentally writes a likable character, no one trusts them enough to not “betray” their audience and ruin the character, to get invested.