I prefer the old classifieds section for the following reasons:
1) I can see more threads on one page
2) I don't need to see thumbnails of the gear - I can tell by the brand or model of the item if it's of further interest to me, if I've never heard of it before, I might go into the thread to see full size images.
3) The thread conversation on an item usually has an influence on whether I buy an item or not. People might get a question answered within the thread which may lead to another question etc, a couple of posts down and you've got a history of the item or some important information. That's all visible quickly in the old threads.
4) I don't mind people bumping. They can do it as often as they like, I just move past and ignore that post.
5) Without bumping, price changes/description changes might not be as obvious to potential buyers. With the new classifieds, the threads stay in the same position, you'd have to be actively looking for that item to see if it had changed price etc...
I'd say the best option would be, if it was possible, to adjust the old classifieds to force a price and location, but otherwise, leave it as it is.
Obviously, I'm happy to pay a fee for the privilege as an (all too) regular user of the section!