- Content is my domain, i.e. the project. It contains dispositions etc. related to my topic. This is not a theme’s domain.
- Theme is in most parts look-and-feel/UI. Something that could be switched out for something prettier if needed.
- There are overlaps to the above, but any improvements to the current archetype lookup will have to take the above into account. I would be really surprised if a theme started to provide content overrides.
So, I see that there are different views on the above. I also see that the current model is not perfect. But this is an open source project. Create a proposal with a design and follow up with an implementation. I have spent a fair amount of time on the archetype system (we had a release not so long ago about it). To redesign this would probably be two days of work for me, including test and documentation. That is not currently a priority for me. But if someone else has that kind of time to contribute to this, go ahead.