I'd realy liked if there were more unic different uses of specific materials.
i.e.
general uses: u can make this thing almoust of everything: like making
blocks,walls,stairs e.t.c. No mutter what rock, wood or maybe some other materials u have u can do this.(it is implemented alreadypretty nice);
special uses: only form 3 to 6(or maybe some narrow group of them) types
of materials can be used for this.(like barrels and bins made of wood,or bolts - wood, bone, iron).
unic- u can use only that kind of material for this only or it gives really good
properties to some items.(example boxite for lava proof parts or even adamantine wich is pretty much like strategic resource).This things should be not so nessesary but still pretty usefull(dependant on material quality). and should be treated as strategical uses.
It is still possible to make some special properties wich separates this material from others.
Also it would be good if items had some properties i'e chalk walls would be less resistant to damage but don't crack(witch can move to neighbouring tilesand make walls susceptible for damage) on heavy object hit,so u can use it as one time save your granite or mramor walls.Glass walls pretty fragile, but they are pretty cheap and shatter on destruction having chance to wound some one nearby,and after shatter it can be like weak trap damaging unarmored legs until cleaned(dependant on stack one tile range from shattered object) can lead for some fun(like mad dwarf hit glass object, or even on sieges).
Some materials can make (un)happy thoughts e.t.c., some can be pretty much invisible in dark, to creatures with bad vision or head damage. obsidian floors and walls in pit and wait till nasty elf tambles there in dark.
Or even stone traps made out of bag of chalk,coal,ash , or talk powder can almoust deal no damage but blocking vision(less u can see while in and also less what's going on there), or causing wander till dust settles(for chalk and talk u can mark em to be better seen in dark therefore better targeting). Or just drop bags of chalk powder on some one head by using preasure plates.