Add a "Quick Reply" box at the bottom of threads. This is a popular feature because not everyone wants to spend the time going to another page to create a post.
We will probably do something similar with a modal overlay, where you click the button and the reply form overlays the page till you are done. Basically, it gets what you want, reply without a pageload.
Allow posts to be edited more than once. As far as I understand things right now posts can only be edited once, and then the "Edit" button simply disappears. This can be troublesome for obvious reasons. (After some testing I may be wrong about this one, or it could just be a bug on my end)
You can edit more than once, but there is a time limit. This one's a balance issue, so help me get it (I know it needs to be longer, how long is key).
On philforum I remember complaints about people materially editing posts after they have been replied to, and there's opportunity for clear malice. In addition, with ability to edit forever moderators would have to monitor content forever (otherwise I can edit in spam links later for example).
In short, there has to be some kind of limit, and sure, it can be longer than what it is now. What are your thoughts? Where should the line be? A lot of sites give you a few minutes, I'm thinking the absolute maximum should be something like half an hour and we only do 5.
My best guess at a reasonable improvement would be 300% of our current limit, at 15 minutes. What do you think?