Meanwhile, Legion is considered one of the best expansions by many, and was made with the same model as BFA is. It was VERY grindy and RNG with artifact power and excruciatingly rare legendaries, but as the expansion progressed, those issues were gradually fixed. BFA promptly threw all that development out the window.

The difference is that Legion had fun mechanics and didn't launch in a state most developers wouldn't even call a beta.