>>531112863
Because of a combination of good lighting, phenomenal art direction AND they are good at making art, it's one of the few things blizzard is still actually capable of doing.

A lot of games with stylized art styles have inconsistent artstyles, with overwatch you will notice that none of the surfaces are too busy, nor are they overly flat.

There's an old TF2 paper that dives much deeper into illustrative rendering and it's a quite fun more technical read.

https://cdn.steamstatic.com/apps/valve/2007/NPAR07_IllustrativeRenderingInTeamFortress2.pdf