There was little that was new in Mueller's statement, but he highlighted the things that are most important.
1. He knew from the beginning he couldn't indict the president [due to crazy DoJ policies].
2. He was mindful not to caste a prosecutorial shadow over an unindicted president unable to defend himself in court.
3. In terms of the Trump campaign, he investigated a narrow issue (conspiracy with the Russian government) and didn't find sufficient evidence to bring a charge against Trump.
4. Nevertheless, he couldn't proclaim the president's innocence of obstruction of the investigation.
5. He intended to pass the baton to Congress to make its own decisions about impeachment.