How about only being able to bump a thread if it has a reasonable amount of responses like say10 and let's say about 100 views which would indicate that their is some intrest in the post.And then again only another 50 or 100 views further being able to bump it once more, after that everybody would have had a chance to look at it and had more than enough time to respond to it.Even better only being able to bump a thread on top of that if you commented on it.

regards
v/man