Or there could be a 'Top Discussions' side by side with 'Top' so there's a different filter for people looking for news (which you want to be recent and not obscured by long running threads) and people looking for discussions (which I'd argue will be more valuable if the popular ones are kept around for a while).
Open for abuse, most definitely, but if the purpose of this site is to build community, I think those topics that get discussed should be more easily accessed. Ideally people would appreciate some valuable discussion and upvote the thread, but this thread here is a perfect example of one that should probably stick around for a while, but has nearly 3x as many comments as upvotes.
Just throwing ideas out - tell me if I'm crazy.