Nintendo's Classic Games Selection and other features won't hit until 2018 because Nintendo wants them to be as good as possible.
Nintendo has had a pretty strong E3 showing this year, unveiling new Metroid games in development, wowing everyone with Super Mario Odyssey, and hosting successful esports tournaments with Splatoon 2 and Arms.
But one thing they didn't dig into too much is their Classic Games Selections service, which will give you a new classic game each month (some with added online features), and will be launched alongside an annual subscription fee required to play Switch games online. The service was originally due in 2017, but was delayed into next year. Streaming services like Netflix, and even a web browser, are also currently not included on the Switch.
Polygon caught up with Nintendo of America President Reggie Fils-Aime during E3 and asked him about the Switch's online services. “As Nintendo looks at the overall online digital experience there's a recognition that there's a lot of work to be world class", he told them, adding that they "need to get our digital environment world class" before they feel comfortable releasing it.
He said that this included Virtual Console, as well, which is surely one of the Switch's most requested features. Hopefully we'll have a definitive date at some point, as well as confirmation of the consoles we'll see emulated.