I would love to see tantruming become more inter-related with social aspects of the game, like grudges and personalities. I don't think it makes sense for an entire fortress to break into tantrum at the death of 2 children, just because those were friendly with everyone. It would make more sense if for whatever weird reason, all dwarves happened to have a 'breaks easily under pressure' trait, but with that situation being highly unlikely, it feels too superficial.
On the topic of grudges, I made a suggestion a while back, which I think would fit well with new tantrum mechanics:
http://www.bay12forums.com/smf/index.php?topic=140912.0Thinking on it some more, it might be an idea to abandon loss of a friend as a direct cause of tantrum alltogether.
Instead, death of a friend, or other traumatic event will put the dwarf in an 'on edge' state of mind. While in this state (duration and or severity could vary for different stressors), events that can lead to a dwarf doing tantrumy stuff like punching and toppling will have more severe effect. For example, taking my grudge suggestion, it would increase the chances for the bad things happening, instead of relations getting better.
It requires some splitting up of events into two categories; stressors, that will cause the 'on edge' status, and annoyances, which give bad thoughts and can lead to tantruming.
Besides grudges, I can think of sleeping in the mud, caught in the rain, drinking the same old booze, stung by a bee, things like that, that would classify as 'annoyance'.