How about offering a longer or an infinite (preferred) period for editing one's own replies and discussions?
That will allow users to build some nice content piles with updates and more information information added over a period of time. Similar to how we have been seeing in XDA forums for years.
For example, when developing a thread for bugs, more bugs can be added or segregated in the first post over routine edits instead of all the data being lost across the discussion spread over multiple pages. This makes moderator's jobs easy and also helps users in identifying which bugs have already been reported without needing to read the entire discussion.
It can also help some users add additional information towards the top of the thread. This will help somebody looking for a solution by not having him read each and every message of the discussion.
If it can't be offered to all users, at least those with 3 or 4 stars should be allowed to edit their replies at any point.