Generally, knowing a few queries that produce suboptimal results is interesting, but it's not really easy for us to fix specific examples without putting extremely specific hacks into the code, which will cause more pain than gain in the long run. Whenever you tweak some parameter trying only to make one specific query better, you tend to make a ton of other ones worse. The long and short of it is that there is a limited amount we can do here. Accordingly, I'm declining this task.