Apache Solr ships with a number of examples. They evolved from a kitchen sync example and are rather large. When new Solr features are added, they are often shoehorned into the most appropriate example and sometimes are not represented at all.
Often, for new users, it is hard to tell what part of example is relevant, what part is default and what part is demonstrating something completely different.
It would take significant (and very appreciated) effort to review all the examples and rebuild them to provide clean way to showcase best practices around base and most recent features.
Specific issues are around kitchen sync vs. minimal examples, better approach to "schemaless" mode and creating examples and datasets that allow to create both "hello world" and more-advanced tutorials.