Well, I ask this about how much autonomy you would be willing to give your dwarves because, frankly, the idea that wresting control from the player, and giving it to dwarven autonomy is the main limiter on what I can do in making this suggestion.
As for the zoning for commerce part, that was simply an example of "loosening the leash", something else we could do, for example, is simply not assign labors to dwarves, and just have job requests which dwarves fill based upon what job they want to perform that day. If dwarves own their own workshops, that would be significantly changed by what they own.
It could even be a model where dwarves own the resources they harvest or create, and you have to "buy" it from them with fortress funds, and they can simply start setting up their own industries based on their own preferences, and you just post "contracts" to buy certain amounts of products or materials, and let the dwarves do the rest as they see fit, while paying them in money that presumably must be taxed of them.
That would be SIGNIFICANTLY slipping their leash, to the point where dwarves are total free spirits that you have very little direct control over. I'm asking for a matter of degree players would want their dwarves to become autonomous.
If dwarves were all suddenly total capitalists, like in that last post I made, and you had only indirect incintive-based control over dwarven actions, and the little idiots basically were on their own, aside from how much you manipulate their mining habits, or make public works projects, and zoning ordinances, then the system itself has to become much smarter, which means I have to start thinking through many more of these things.
But this would also make the entire class system much less a function of "this dwarf is poor because the player never enabled any labors on this dwarf", and much more a function of "this dwarf is poor because he tends to be lazy, or he was poorly educated, or he was the victim of a workplace accident, poor healthcare, and a lack of a social safety net, or he is struggling against some form of institutional disadvantage."
When we are talking about sumptuary laws, I think it's actually a point for the sort of thing I am talking about - the nobles were actually so scared that the middle class would rise up not in anger, but in wealth that they would be able to effectively replicate the noble's lifestyle, and eliminate the gulf that they wanted between the classes on their own.
(Sumptuary laws included the likes of forcing laborers to eat less refined foods, because laborers were less refined, and their foods should match, while nobles were more sophisticated, and as such, required more sophisticated foods, which is why their multi-course meals were actually a dietary necessity.)
Of course, at the same time, notions of dwarven delicateness, even among nobles, still sounds like so much elf talk, so it's perfectly fine to have a more dwarven social system. The question then becomes "what is a dwarfy social system"? Do I get to arm-wrestle you for advancement in rank? I put up one's skill as a craftsman (in terms of skill rank) as a means of advancment, such that the most skilled craftsmen would be among the highest social rankers, aside from nobles. How much does making an artifact help, or do we go by number of masterworks created? etc.