CSS - One attribute to rule them all
It is a real struggle to style the elements today because one cannot add the classes he wants to one particular element.
We should have a generic system for this that would look something like adding the attribute
class-xyz="class-1 class-2 class-z", that would add the listed classes to the
<xyz> HTML tags within the web component.
This attribute would then allow the user to set any class he wants on any element. Preventing this makes styling the components a massive pain.