I'm having a lot of trouble relating what you quote to what you type, Shadowform... Generally when you add a quote from the same page you're posting on, it's to turn it into a more one-on-one conversation, where the posts are more heavily related to each other. And after you opt for that sort of conversation, you don't just suddenly ignore the person.
What exactly did I ignore? You mentioned something about ladders, I pointed out ladders didn't exist. You expressed confusion at why I pointed this out, but since you were apparently waiting for an answer... I pointed it out because if it doesn't exist, there's no sense in worrying about it.
Second, forums like this are NEVER one-on-one conversations; I can quote someone whose quoted someone else whose quoted a third person, and a fourth person can quote me. The intent of a forum is to hold public, group discussions - if you'd like to have a personal conversation though, feel free to PM me. I like tossing ideas at other people to get feedback on them.
Aside from that, I find your exacting dissertation on what Toady may or may not do, and what he can or cannot do, to be worthy of ; you can guess, but you can't know what will be a problem, you can't know how dwarves/players might weaponize a metal cooking pot larger than they are, and you can't know how random any given feature is as far as the code is concerned. As an example, it might seem to some people that Toady's work with farms, generating human towns, and economy has nothing to do with night creatures, adventurer-made buildings, sending your armies off your fort, or keeping items from being scrambled at fort's end, but they all have one issue in common; saving and relating sites in the world. He is working on this apparently random set of features because they do go together. Likewise, both main uses of pots might end up being easier to do at the same time when the "cast cauldron" job is added.
Perhaps I'm not explaining it very well, but I hope you understand anyway.
During that, I realized it would be a fine idea to ask about this in the Future of the Fortress thread. So...
I'd make two arguments here.
First, this forum is titled 'Suggestions'. It's used to toss around ideas for things that could get added, removed, or changed in DF. I had an idea for something I thought would be nice to have added. So, I made a suggestion. Naturally I don't expect instant gratification, or that the idea will necessarily get added, or that Toady will look upon my genius and declare "OF COURSE! HOW COULD I MISS THAT?" But I to think that he reads the forum, and I do think that if I can make a strong argument that it serves a meaningful purpose, adds a utility not otherwise present (in this case, making use of poisonous materials), could realistically exist in the time period Dwarf Fortress is set in, and pique interest in the mechanic, then it stands a much better chance of being added than if I was to just say "Yeah this is cool add it plz."
I really don't mean to come off as rude, and I'm really not trying to be rude, but it kind of feels like you're calling me a fool for making a suggestion in the suggestion forum because I haven't provided a detailed analysis of how you would code it, how it would effect civ interactions, how it would impact hoary marmot breeding habits, as well as covering for every potential way in which a cauldron could conceivably be used in a real life scenario, such as storage, cooking, how re-using a dirty pot for cooking could effect fortress health or contaminate the food, etc. This started as one idea for a simple structure ("Like a magma pump, but loaded with a specific amount of fluid instead of drawing from the world around it") and somehow spread from there into this.
Second, while it's true that I can't see into the future, but nobody can, and Toady is nothing if not willing to spend significant amounts of time making sure that something he wants to happen will happen. The entire game is an example of that, but to be more specific, the recently overhauled combat system (read some of the bug reports from when he was coding this; murderous eldritch gophers do not strike me as intended behavior) is a good example. Again, if it's an idea he sees and likes, it's much more likely to get added to the game, at some point, eventually, when he gets around to it, but added nonetheless.