Along with YouTube and SoundCloud, adding a separate option that would simply just be a browser. If this was added, you could play any form of media easily. The screen would be synchronized with other players, and upon opening it, it would take you to google or another search engine. If you wanted to watch a video or movie off the browser, you could just press the full screen button and let it do it’s magic.
I’m aware of the egregious amount of work it takes to get different formats for the media player to run, but the options we have now are just too limited. The theater can’t even be used to watch movies unless you can find some youtuber-made original movie. Adding a browser would not only give access to more content and material, but also keep the developers from having to work on different formats, thus giving them more time to work on other features.