Speaking of staying on topic... 
I'd like to see nobles stop demanding things you don't have the materials for (unless they are truly mad or extremely unhappy), but I'd like to see some new types of demands and requests to keep them interesting.
If something a high ranking noble likes shows up for trade at the depot, he should be able to demand that you buy it for him. Think of it like going to Wal-mart with a pack of spoiled eight year-olds.
Moreover, importing things should count towards production mandates. So long as he get's his large blue diamond, the mayor shouldn't care where it comes form.
If nobles are going to demand stuff we have to import materials for, we should at least be given a large advance warning, so we don't have to import two dozen types of exotic materials, just in case the Baroness' consort decides that he absolutely has to have a schist table in his dining room.
With even just a few of these changes, I'd be happy to see noble losses get more "fun".
If only moody dwarves and nobles would also have the brainpower to ask for stuff we can provide..
eh.. in one of my games the count consort mandated that a build an adamatium item... with no adamantine or anything related to it availlable. There was none! And of course the hammerer is only too happy to deliver punishment..
The only noble i like having around is the Dungeon master since hes doing some usefull work and taming, and dont usually ask for much.
All the others are parasites.. they dont bring anything positive.. they are only trouble, whine all the time and consume precious ressources, and when we cant get it for them sometimes one of our hard worker dies or is useless.
If nobles actually did anything good they could do this:
- Decreasing the buying prices of stuff and increasing our income with their influence. They do change the prices of goods but that menu is so confusing i never know what changed by what amount..
- Caravans are always bigger when the nobles are around, better migrants shows up with more usefull skills and/or upgraded attributes.
- Caravans could get an upgraded list of things you could get when nobles are around; the big guys have friends and contacts and you can use them to import stuff you normally could not. Maybe a Duke can allow access to almost everything.
- Maybe with their influence, you get less thieves/snatchers/ambushes due to increased "background" security. But at the same time you become an even more visible target so super beasts shows up more and sieges are larger.
- Philosophers could make dwarves happier? Or maybe the philosopher is an educator and increase the skills the kids have (some sort of school)? Right now i use them as lever activators since they dont do anything else.
- The tax guy... if tax money allowed us to buy special stuff from caravans, allow us to acces new special buildings, influence the "global" market (with blocus, embargo, monopoly whatever), or bribing some other faction to influence their military/economy/society/diplomacy in good or bad ways.. that would be usefull. Tax is used by the '"state" for the needs of the nation.. so i wanna see it happen.