First and second are probably features for some people, third is solved, according to the source. I wonder if it would be a good idea to revive plugins - back

First and second are probably features for some people, third is solved, according to the source. I wonder if it would be a good idea to revive plugins - back in the day we used object tags with links to the plugin to install to render the media. Maybe something similar can be done today with a link to some js that does the rendering. So you can have an img tag with mime type image/x-spif and a link to a js (or in the future, web assembly) handler in case there is no native support. Web browsers are basically operating systems now. We should be working towards letting people safely install extensions.