@Charles Wide scale change is unlikely to happen any time soon, because our founders actually work for Twitter now, and only take care of this site in their spare time. That said, there are some things to consider about your suggestions, and we thank you for making them.
I’ll address your last suggestion first. There actually is a time stamp on each answer, but it’s hidden. If you hover your mouse just to the right of the ‘Flag as’ button (which is below each post), you’ll see a red paragraph symbol. Hover on that, and you’ll see when the answer was posted. This also works as a permalink, so if you right click on it, and choose “copy link location” you can then post it elsewhere (which can be helpful regarding your suggestion 2, above).
The reason it’s hidden is because we value a less cluttered look to the site, which is also why we’ll likely never allow folks to insert graphics, videos, gifs or pictures (numbers 3 and 5, above) or change the font size of the poster’s name (number 1).
As for number 5A (?), you can see questions and responses given by a member by going to their profile page, providing their privacy settings allow it. In the search box, you can type “username” to search for a particular member or ”@username” + whatever you’re searching for to find something said by that member. About the only thing you can’t do in search is to search by date (which would be nice).
It’s actually easier to read a narrower block of text than a screen-width one, so that probably won’t change (# 4).
We use topics (tags) to further break down the categories, but probably won’t create whole new sections for it. You never know, though!