What made Arcane good ultimately was that so many characters in the conflict made good decisions and tried to do smart things.
A lot of lazy writing relies on people making irrational decisions or having lots of miscommunications. This show highlighted the difficulty of the context rather than individual dumb decisions or miscommunication or one-note characters: it was about the economic and ethical backdrop of the situation, and how characters responded to it.
The visuals, music, voice acting, and all of that was great, but it was the writing that tied it together. Some of the most interesting heroes and villains.
And it's shockingly a video game adaption, which is why I didn't bother to see it until three years after it came out, now that season 2 is about to come out.
