The most appropriate solution would be having the admins find and delete these dud posts before other users have a chance to say "Lock this" (the latter of which I'm guilty). These threads are rarely actually locked by the topic creator, and sometimes eventually locked by an admin.
So, yes, there are many lock-worthy threads, but it's generally better just not to post in them and thus let them die. Also, just because an old thread is bumped, doesn't necessarily mean it should be locked.
On a separate note, another problem I often see is good threads getting a lot of said dud comments, forcing them to die or get locked.