A lot of the "boilerplate" of WebComponents disappears if you entirely ignore the Shadow DOM, and you can just do that.
They can support objects and arrays as attributes in the same way as the old Progressive Enhancement era (jQuery/Knockout-era) web: via data- attributes and the dataset property. Similar to that era you probably still want to support JSON serialization/deserialization to those attributes for SSG/SSR support.
They can support objects and arrays as attributes in the same way as the old Progressive Enhancement era (jQuery/Knockout-era) web: via data- attributes and the dataset property. Similar to that era you probably still want to support JSON serialization/deserialization to those attributes for SSG/SSR support.