Can we have a 'my discussions' button that shows all threads I've posted in?

http://boards.na.leagueoflegends.com/en/player/NA/MorikTheMad

This is kind of hidden but you can access it by clicking your portrait when logged in or a name in a post to see their post history.

Click on your summoner icon in the top right, or your name in general. It'll show you a list.