This is a two part idea I came up with when I found out there are a lot of things you can make with raw materials and not with blocks, and then the subsequent discovery blocks are smaller and lighter than the raw materials. I did a search and while I will have to retread some ground, it is to get to some new stuff.
First of all (and correct me if I am wrong in any case), there doesn't seem to be a whole lot of incentive to create blocks. They reduce construction time, but that is obviously offset by the time the mason or carpenter spends making them (I haven't dug into if this increases or decreases overall construction time), I am not sure if constructions made of block have higher value than rough constructions built of raw material, but if they don't, they should. Aside from that, ifwhen goblins and forgotten beasts gain the ability to destroy constructions, the ones made of blocks should be more resilient. The other reason you would want blocks is that they can be stacked in bins, thus being easier to move en-masse as well as taking up less space in storage, the compactness is not too important for wood that you collect as you need, but for stone, this can be very handy since you end up buried in stone as you dig deeper and level up your miners; sadly the bulky boulders are required for most things which actually creates incentive not to make blocks.
I propose that blocks be allowed as a construction material for more things, maybe large items like doors and such may need to stay whole stones (or perhaps some stuff like statues take multiple blocks), but crafts, pots, bins, etc, should be able to be hewn from blocks. As with constructions, using blocks reduces the time to complete a project since much of the excess is already cut off. This would make blocks much more useful, and cut down on rock clutter without resorting to quantum stockpiles (something I feel is an exploit).
The second idea is a two parter. First, manufacturing jobs (at least the ones using wood and stone) should {have a chance to} create scraps. When creating something from raw wood or stone, you should get some scraps as well as the finished products; unskilled dwarves might even have a chance to produce just the scraps (ie. they botched the job). Making something out of blocks would not produce scraps since scraps were already generated when the block was made (an alternative is jobs with blocks and jobs with raw materials both make scraps, but blocks produce less or produce them less often, but it seems to me it would be less headache for blocks to just produce no scraps at all). Additionally, construction jobs from raw materials should make scraps (lumber has to be cut into planks and stones have to be made into blocks to actually make a solid wall or floor), as should hasty demolition (with the option to spend extra time deconstructing the building or construction piece by piece to retrieve the building materials whole) including that done by building destroyers. I also think when mining out stone (excepting ore viens) miners should sometimes leave rubble instead of boulders and smaller trees should be able to be cut down to obtain wood scraps instead of logs. This scrap isn't usable as is, but can be used as a raw ingredient for other materials or possibly have other uses (such as burning wood scraps to make ash or charcoal). To tie in with the first point, scraps should be stackable in bins (or maybe barrels), so even with the extra scraps lying around, making blocks still saves you space (10 boulders might turn into a bin of stone blocks and a barrel of rubble, a savings of 8 squares in your stockpile)
Obviously these materials need to have some use. I am going to tackle wood first since it is simpler for the intents of this thread. Jobs involving wood would produce wood scraps; for simplicity, and since the uses for the scraps don;t really depend a whole lot on what kind of wood they came from (unless we start getting into the minute details that make hardwoods and softwoods useful for different things IRL), these scraps should just be generic wood scraps. Wood scraps, regardless of source (left overs from crafts, trees too small to make logs out of, crappy craftsdwarf, etc.) should be able to be turned into plywood blocks. This plywood would have less value than other woods, but your dwarves should be able to take regular logs and some plywood to create veneered plywood (unlike plywood, veneered plywood is specific material types e. oak plywood, pine plywood, etc.); items made from veneered plywood would have less value than something made wholly from that wood, but you can veneer multiple plywood blocks from one tree, so the total value of all the plywood items is a bit more than one item made from that same tree (basically it is the same as real plywood, stretch the supplies of nice wood by cutting it real thin and gluing it over cheap scrap, but the real deal is still preferred by those who can afford it). Some items such as crafts or bolts can't be made with plywood, but it can be used as a substitute for most things from buildings and constructions to barrels and furniture.
Dealing with rock scraps carries a prerequisite: cement. Cement has already been suggested and is in the eternal voting thread, so I won't cover everything here. The basics are that you can take limestone and volcanic ash (which would need to be added, I believe) to the kiln to make a bag of cement (other materials might be able to be substituted, I'm just going by what the first cements [such as what the Romans used] were made of). A bag of cement and a bucket of water can be used to make many of the same things stone can such as pots, doors and walls, it can also be turned into blocks for construction. This is where rock scrap comes in: like wood scraps, rock scraps are generic and low value materials with the ability to stretch other materials. By using the rock scraps as aggregate, you can make concrete items. This has two effects. The first effect is that of stretching your cement stockpiles, very important if you embarked in a region that requires you to import the ingredients, because you can make multiple items from one bag of cement (for instance you can make a cement door out of one bag of cement, or you can make two concrete doors using one bag of cement and one pile of rubble, though you have to make the doors in pairs). The second is that concrete items and constructions resist wear, tear, megabeasts and goblin sieges much better than cement items ifwhen it becomes an issue.
On a side note, ifwhen megabeasts and goblins learn to smash walls and other constructions, concrete should also be allowed to be used as mortar on constructions made of stone, bricks or stone, concrete and cement blocks to increase the constructions' resilience (one bag should cover multiple squares). If you don't use cement you have dry stone masonry, resilient enough on its own, but not as good for fortifying areas.
Questions? Comments? Concerns?
Requests for expounding expanding and elucidating?