It would certainly help but would probably be too much work. I actually proposed something similar to counteract bots where every newbie's first post needs to be approved first before it goes live. Most didn't seem to be a fan of it because of the workload it would produce and theymos said it would be too difficult to implement.
Many of the low quality threads have been either locked or moved to off topic and there's many more to come. We're probably going to get much harsher with what is allowed there as well but Signature Campaign operators are also going to have to get more strict with how they run their campaigns and if they don't their signatures will be forcibly removed.