Yes, current page and section name where the thread is located. That's what appears in the Echo notification, no? I doubt it's necessary to store original page and heading. Usually when a thread is renamed or relocated, it should either be something obvious like an archive subpage, or someone should have added a note/template saying “discussion moved from otherplace”.
Some kind of start-date would be good, either date of OP or date subscribed. I'm inclined to prefer OP date: do I really care when it was that I started subscribing? And what if I unsubscribe then resubscribe? The original-post date is a property of the thread itself and is the same for everyone. Plus it's the right answer for “how old is this? when did it start?” (Sorry for being verbose, I'm thinking this through as I type.)
Date of most recent comment, to indicate freshness.
An indication of overall activity on the thread: number of posts, number of unique participants. Maybe also an indication of size: number of bytes or words.
Some web forums in their topic lists also display the usernames of the original and latest poster. I feel this gives too much prominence to those two people over the other participants. Is it practical or even useful to list all people? OP name could be relevant in some contexts like Teahouse or ANI.
Nice to have: Ability to sort on either date, and filter on these plus namespace, number of comments, number of participants. If subscriptions are never truly removed from the database but just flagged for don't-notify, an option to show unsubscribed discussions (as distinct from never-subscribed) could be interesting. Search box, or just use browser's find-on-page?
Thinking outside the box, imagine having a personal comment/description/notes field for each subscription. Often the topic heading doesn't well reflect the content of the discussion. Or I might want to record my own reasons for wanting to follow it. Managing these descriptions is more heavy-weight than the simple un/subscribed state, would people use such a feature?
Actions to perform: unsubscribe, resubscribe, delete, add/change description. (Mute notifications for x days? Probably not worth the implementation effort, if resubscribe is already an option.)
Flag for follow-up / pin item / mark as important? Maybe, but again it would be shaping a lightweight subscribe action into a lot more.
As usual, I've gone too long on this, but hope there are some parts you can pick out to support a use case or user story. Shorter answer:
- Info to show = page, section, start date (first post), last active date (most recent post), num. comments, num. participants, length (words or bytes).
- Actions/features: unsubscribe/mute, resubscribe/unmute, delete/unsubscribe; edit personal note; sort, filter; select view style (list, table, icons).