Thanks for the feedback.
At present, I don't believe that there is a centralised list of all forums across all courses that you're enrolled in and have available to you, but we do have one on a per-course basis. I'd love to make a holistic view of that course page, and we'll have to look into this in terms of performance to see whether it is feasible or whether there is a better solution that we haven't considered.
Although I've not included it on the screenshot in the subscription proposal (http://docs.moodle.org/dev/mod_forum-subscriptions), I was hoping to include the options there too so you can see both your subscription status, and your digest status. Where applicable (e.g. you have the appropriate capabilities), you'd be able to control these settings too.
Do you feel that these address your concerns?