I would recommend not looking at most of them unless you have a specific goal in mind, and then taking it one step at a time (while asking for help here as needed!).
You’re right, there are an enormous amount of possibilities and they could be organized better… and we’re working on it, but it’s a long road. The number of configuration options is currently greater than what any single person can form a mental model of… so it’s no surprise that you’re overwhelmed by possibilities.
We can! every single post here will be read by someone working on Discourse. After reading your posts last week I started working on a feature to add tags directly via the tag page. This is feedback we’ve received a number of times so it seemed about time we try it.