Well, for other games, each user makes their own topic and posts all their ideas in there.
If you don't mind, I think I'll do so here.
1. My suggestions for technology
Go here:
http://www.bay12forums.com/smf/index.php?topic=62629.02. My suggestions for music
Go here:
http://www.bay12forums.com/smf/index.php?topic=62634.0Most of what I suggest seems planned already, though...
3. Creatures killable only by a certain type of material.
Go here:
http://www.bay12forums.com/smf/index.php?topic=62632.0Seems that this already exists in game. So much for that suggestion, although, I would like a simpler method.
4. Modding cave generation.
As far as I know, the player does not have much say in how caves look/are generated.
Why not allow for scripts/formulas made by players to be used for cave Gen?
That way, if a player wants, they can make every cave a sphere with water at the bottomn.
Or, caves are only small, winding paths. Or, caves vary between these 2 suggested ideas and the current Cave style.
I would like this a lot.
5. Blueprints/design papers (or whatever you want to call it)
I noticed that in vanilla DF, you cannot forge long swords at the forge or craft blowguns at the carpenter's shop.
Well, I have an idea for foreign items.
To build an item your civ does not use, you must trade for the blueprints, ask a migrated weaponsmith to forge some so that all metalsmiths will be able to if they learn from him/his blueprints, send a spy to an another Civ to steal the design/blueprints, or plunder the designs/blueprints/models in war.
Ya, this requires some other stuff ot be implemented, but they will.
Another idea out of this one is compelx/advanced objects require the builder/architect to grab the blueprints and haul it to the construction site with them and build using that.
Afterwards, they have to take the blueprint and bring it back to wherever or something.
6. Immigrants from other races
If this is enabled in the init files, Elfs, humans, goblins, whatever should be allowed to migrate to your fort.
Although it would probably be rare, it should still happen.
There are many factors that could influence an occurence of this.
For example, an Elf that tolerates dwarfs and is persecuted for that flees to your fort (in fort mode, any dwarven settlement in adventure mode/world gen)
7. Offscreen settlements getting abandoned
Sort of building on immagrants from other races, if a nearby settlement is attacked, the people living in it should flee to your fort (in fort mode, any dwarven settlement in adventure mode/world gen)if your civs are on good terms.
8. Idea for trade
Sort of building on Immagrants from other races, every individual civilization should send caravans to you, not only one caravan from the entire race.
This probably will be implemented when caravans are tracked offmap, and it may even already have been considered.
9. Slavery
The player should be able to request slaves from caravans/buy them off caravans.
They can be prisoners of war, crminals, etc.
10. Mercanaries/indentured servants/hired labor.
It would be great if the player was able to hire Mercanaries to fight their wars, offer people who want to migrate but can't to come here, all expenses paid, and work x number of time to pay off the money you spent. This could also be a method of getting around the not coming to your deathrap thing.
Hired labor: Ask a civ to send workers to your fort of proffesion x, and skill y. You then pay the proposed monthly/yearly fee (Depending on what terms you agreed to).
Wouldn't it be nice if the player had the ability to do this: "Hey, whoever migrates to my fort will recieve xyz". Helps if the last migrant wave was too small.
11. Explosions
Example scenario:
"I think I'll take out my iron pick and mine out this iron vein." The dwarf takes out his pick and begins digging. when the pick hit's the wall, it produces sparks. The sparks come in contact with the invisible flamable gas in the tunnel. That dwarf has discovered the bomb.
There should be an option in the init do disable explosions for those who don't want to play with them.
More to come as I think them up.
Sorry if some of these were suggested already.