Well... "Web Components" need to fit in a lot of situations and yeah Riot don't want to be categorized as "Web Components" But it is a really Smart UI Library so it needs to grow and accept some side use cases that the original authors didn't thought about like multiple yield. I think is near the roof in what it needs and just need bug fixes like the "if" which keeps evaluating the tag and all of that.
Also, its complicated if you want it, I mean, I have been using from 2.0 I think, and the syntax has almost not changed, maybe in the route system which maybe will become optional. But... I don't know XD