Currently, there does not appear to be any way to get to a linked URL without first opening up the kbin comments page for a thread.
This doubles the work a user has to do in order to reach the linked URL, and also increases the load on kbin since users are loading twice as many kbin pages as they otherwise might.
Each thread listing already has a “Comments” link that brings you to the kbin page for that thread. So the main title should link directly to the linked URL.
I think the title opening the thread is good. IMO for image posts the best behavior would be that the thumbnail opens the media preview. For site links I would go with the thumbnail opening the link, and replacing the thumbnail with a large arrow if there is no image.