As Shonai_Dweller said, he does care, and he does try to adjust things. A major drawback with his setup is that he doesn't have the time to run fortresses for long enough to see long term issues himself, and so has to rely on feedback and well written/reseached bug reports (ideally with a save that clearly shows where the problem is).
Shonai_Dweller mentioned 0.44.10 for a reason: that's the version where the new system was introduced in a completely unbalanced state, so experience from 0.44.09 doesn't account for much.
In order to balance the current take on the system again Toady would need solid data on what is too much and what is too little, and I don't think there's enough experience in the community to determine that yet.
One of the changes made to the system was to divide memory slots into groups, so not each and every instance of the strongest kind of thought would occupy every slot, but leave room for weaker thoughts that hopefully are positive to make it in, and I think the impact of seeing lesser body bits (such as teeth and fingers) has been lessened as well.
My personal experience of the system is limited, as my fortress is just short of 10 years old, I think. So far I haven't had anyone go over the edge, although I've had one I thought lost because he kept slipping further into stress even when I did everything I could think of, but he eventually turned around. I've got one or two cases of yellow arrow stress as well. It can be mentioned that my fortress sees its share of corpse hauling, as goblins and undead show up a fair bit (although my prisoner execution device happened to end up in a reanimating biome, converting some killed prisoners into undead, which should cause less stress when hauled (assuming they are killed [again], of course). Most prisoners get atom smashed, though, but there's still ones killed by the delivery process before then can enter the smasher.