Alchemy has a million and one possible things you could add to it, perhaps even having multiple tiers of alchemy labs, like you do with mechanics. Perhaps if you get enough or certain kinds of radioactive reactions, you can have an advanced alchemy lab (mad science sanitorium?)
A lump of highly radioactive material could be dangerous, but possibly used as a fuel source or requirement for more SCIENCE!
Also, there are very limited ways to melt ice (or anything else). Toady never put in an option to build a bonfire, or anything like that. Or even a fire trap. Obviously, we've all been pumping magma to do these things, but a more limited way to do it on a smaller scale could be nice. For making one shot fire traps that are faster and easier to build, but not reusable (or as lethal) or heck, just for melting ice for drinking water for the wounded.
Although the possibility of using radioactive waste to melt drinking water.....hmmmm.....
Just tossing out more ideas.
The bolded statement is something I have great interest in. Not a "nuclear reactor" sort of thing, but I think it's well within universe to add a rock that constantly leaks power that could be harnessed by alchemy to produce fuel.
The problem I am facing with fires is how to safely start them. Since dwarves produce workshop products right beneath their feet, there's a good chance that they'll wind up lighting themselves on fire. As an alchemical disaster, this was quite humorous, but makes the practicality of intentionally lit fires a bit difficult. Toady stated in the development logs that this is a planned future feature, but I will look into some other mods that deal with this concept to see if they have a more effective methods of dealing with unwanted side effects. Maybe I can track down something that works and permissions to use it.
Also, am I doing something wrong or are bog trolls so enormous they can't even be killed by dropping atom smasher bridges on them?
Atom smashing has been greatly "nerfed" since 40d. It's not a surprise to me that it isn't working on bog trolls, especially if there's more than one of them. It's really only useful for garbage disposal nowadays, or as a light defense mechanism against smaller creatures (i.e. goblins).
Sorry, but I think siege engines are hardcoded. That's why in some total conversions, we have ballistae even when the setting is OUTER SPACE. Kinda weird.
This is correct. Unfortunately, it makes ideas like Carn's stationary bolt thrower impossible. I will, of course, revisit some of these ideas if new versions of DF make them possible.
Here's a thought I'm planning to implement in my current mod: Research.
Have a reaction that consumes experimental alchemical resources and requires the presence of glass vials, and has a 1/100 chance to output a rare reagent. This reagent can be further reacted in similar reactions until you produce some new kind of precision tool. This can then be used as the requirement for a workshop that allows the production of new weapons, substances, or more research.
For example, you might have a "Experiment with gold and silver" reaction that has a 1/100 change to yield raw orichalcum. This could then be used in the "Purify raw orihalcum" reaction that has a 1/50 chance to produce purified orihalcum. Then, the Orihalcum Alchemical Forge would require a unit of purified orihalcum to make, and would allow the player to further synthesize pieces of orihalcum or forge orihalcum into weapons or tools.
You could probably use this idea in creating tiers of technology in your own mod.
This is similar to my line of thinking for second tier advances, though how I go about the "chances" for advancement may be a bit different. There are literally a million things that can be done with this idea - which is part of the reason I'm so surprised that it hasn't really been explored very much. Some sort of synthesis of tech advancement and the "heavy armor" concept is something I would like to play around with.