When changing states of many tasks it would be quicker if you don't have to open each task to do so

The primary reason for this is that we'd like to encourage people to comment when they make changes to the priority, status, category, or assignee. A lack of comments and insight into changes generally leads to a lot of "why did we do that?" down the road. So, while comments aren't mandatory, it's definitely something we want to encourage.

That said, we have been thinking about a way to streamline this process so that it is more convenient. Unfortunately, it's fairly low priority relative to things like the API and milestones.