[YShin]

Shadows on subtitles, in my humble opinion, gives a better looking to the experience. It could be something to be turned on or off in video settings.

The visual gets a lot better.

[Tuxon86]

Isn't that a function of your subtitle file and encoding?
ASS sub support shading and other font effect I think?

[magao]

-1 as mandated, -0 as an option. I find a simple black outline to be much more readable than shadows.