I don't support this, people in the medieval era didn't had a lot to do besides working, so they lived to work.
That is not quite true... Since medieval time our society have abolished about 2/3 or at least half of all holidays that were prominent during those days so they did have free time and lives outside work. Although the work was so highly time inefficient that it could not have been much free time, but that is a sidenote (I study history at the university...). Besides, the fortress does work rather differently than the prominent family based medieval economy so the problem of historical accuracy does not really arise, does it?
if i remember correct, the days in dwarf fortress are very short so a daily routine would completely ruin productivity since a miner going to mine would turn around halfway there because it's already time to quit. weekly routines would suffer similar problems.
what might be possible would be a monthly or once-per-season gathering but then it should be long enough for distant dwarves to gather and short enough to not completely shut down a fortress.
in theory i support your idea, but time is too vague a concept in dwarf fortress to use it as a basis for such an important aspect of the game.
You do have a point there, daily routines would disrupt things in civilian work. However many "social" and military bits in the game would flow much better if you could make appointments or schedule in a time when training begins in a barrack and when it ends. By "social bits" I mean stuff like a couple of days long party if you notice your dwarves being more morose than usual, or a monthly festival or religious ceremonies. It might also give a foundation for political frameworks, like elections, debates and such.
It is not as if I am saying that it should change this instant, but it might be time to start thinking about how to facilitate such a change in the future. Maybe the days need to be longer and maybe an other system would be better suited for the game as it is now.
The largest gain with a schedule based system is the ability to gather groups of dwarves (specific or general) at a certain place at a certain time, and I can not really see an other way to make meetings with specific dwarves possible.
Interesting.
How about it depends on the civ to make what the people are comfortable with? Maybe size? Maybe tied in with the fortress economy? I think that's what we really should be asking ourselves, is what would decide it.
So for instance you could pick one.....
1. Schedule Based. (You eat then, sleep then, work then)
2. Job Based (As it is now)
3. Season Based.
Any others?
It might be a better plan to make a combination, have season based for larger gatherings and farming, schedule based for organising eating and sleeping and job based for the work to work actions.