> In my opinion, stricter oversight is beneficial.

I agree; stricter oversight is beneficial for the official app store. It should not be necessary (and neither should Google's (or Apple's, or Microsoft's, or the government's, etc) verification be necessary) for stuff you install by yourself.

> The Maven Central registry for Java libraries, by contrast, requires developers to own the DNS domain used as a namespace for their library.

This means that you will need to have a domain name, and can verify it for this purpose. (It also has a problem if the domain name is later reassigned to someone else; including a timestamp would be one way to avoid that problem (there are other possibilities as well) but I think Java namespaces do not have timestamps.)

> I hope that Google's new approach is motivated by security concerns rather than purely economic reasons.

Maybe partially, but they would need to do it a better way.