The focus in the activity stream is not on the thread title. To me, on a support forum like this, the thread title is generally the most important thing. In the activity stream, the thread title is mashed between the user name and the forum its posted in and so is not easy to quickly glance at. I just want a list of thread titles so that I can scroll through them and find topics that interest me.
About the Subscribed threads.....why is this in a menu? Isnt Ubuntu trying to rid itself of menus?