I also agree with a lot of what you've said.
There are a few things though that already work:

• Infinite scroll: when you click on the cog wheel (propably on the top right corner) you can enable infinite scroll. And a few other options, which I love
• Formatting: I think this just has markdown support with lists, headers, etc. However I just noticed that all headers are equally large
• /sub as main: you can set the default site that is shown to you, to your subscribed posts. This is however not in the cog menu, but in your personal settings

For it to federate an instance must have a user that subscribed to it. On kbin you just search for [email protected]