Argued about how adding painting layer is a bad idea.

A few releases later...

Added advanced grease pencil animation feature 'with' grease pencil painting layers.

...Ok.

Actually, you can make your own layers through the node editor, someone made a video of that. But it's not as easy as having an actual layer feature.

I hope this will be made in the future. At least community-made addon would be nice. Because there are people who (for some reason) likes painting in Blender even if they can get other painting programs such as Substance Painter.

Since they are able to add more and more features with 2.8, if they can't figure out how to make painting layers work I'm telling the adult >:(