I used to rank E7 higher than E9, but upon further introspection, I now agree with the article. The "Believe In" segment towards the end E9 is so powerful. E7 continues to be the most visually-stunning, only beaten by some of the best of Cloverworks and KyoAni's other stuff.
E12 and 13 are the lowest. It felt like they're "contractually-obligated" episodes that would not exist if the series is a wholly-KyoAni original.
E10 is as close to a perfect standalone episode I can find. It's not just the best episode of
Violet Evergarden, but the best of any anime, period.