The game needs abstraction because real time pace isn't a game. What it does now is two things: first, reduce the amount of natural cycles (hunger, sleep, etc.) in a year; second, reduce the amount of time needed for certain tasks (sleep, eat, stationary labor) in favor of moving around (so the player can look at an active fortress).
This works marvelously for normal economic activity, construction and skirmishes, but really has limitations for sieges and longer battles. Ordering your soldiers to run out the front gates takes days, if not weeks. It's impossible to eg. make tactical use of nightfall, because it lasts only two player time seconds.
A solution I proposed some time ago was to change to crisis mode whenever something dangerous happens. Civilians would get the same number of actions per year, but there would be much more days; soldiers and anyone involved in the danger would get more days. This would effectively put civilians in slow motion, allowing the player to pay attention to the invasion, the soldiers to leave their barracks and do some fighting before a week has passed, and have an overall more interesting combat without making it abusable in an economic way. thread: http://www.bay12forums.com/smf/index.php?topic=113068.msg3445346#msg3445346
The problem is, how does the game determine when a "crisis" is? Is it when a hostile creature is on the map? That's, like, always. Is it when combat ensues? Then when does it turn off?
I haven't seen a good solution for this.
It starts whenever dwarves panick in the current setup. It stops when no dwarves are panicked anymore. That takes care of 90% of situations. The remaining 10% can be taken care of by marking stragglers or creatures far below bridges as non-threatening, so dwarves would ignore them (on the inititiative of the player), which would solve another long-standing problem too (the "non-threathening" mark would vanish when one of those creatures managed to actually hit a dwarf).
In addition, floods and cave-ins can also be handled in crisis mode, allowing believable flow speeds of liquids: that will make traps more effective, not less.
Both of those come with problems. As does your suggestion that lever-pulling be a soldier's job.
First off, creatures far away or lower down can still hurt creatures if they have a ranged attack of any kind, or if they are a necromancer. Having "combat mode" end when creatures are outside X range would screw things up with bowgoblins,
Second off, below "bridges" isn't a very good reason for a creature not to scare a dwarf.
Badgers would be even more of an annoyance than they are now.
The biggest issue that springs to mind is a non-threatening creature not becoming threatening until it attacks something.
How does DF tell what a "flood" is? It's just flowing water to the game.
Those come to mind instantly. I may type more when I have more time.