Hi Scott and welcome to the forum,
I moved your post to a new topic as it contains a much broader set of subjects than just variables in rules.
We like to try and keep any given forum topic to one subject, otherwise it makes it harder to have substantive discussions and keep things straight. Your post has I think 11 bullet points, and each one deserves its own discussion!
Having said that, I will try to cover the ground here. If you want further discussion on any of these, please start a separate topic for it - thanks!
Not currently possible; rules can’t be triggered by changes to other tasks (well, aside from the “No longer blocked” trigger, which I guess is an exception).
Not possible in Asana natively. Possible via the rules in our Flowsana integration which work at any subtask level.
Not possible in Asana natively. Possible via our Flowsana integration which has a “Task is assigned to anyone” rule trigger condition.
Rules are strictly project-specific so you would have to create a rule in that other project to set attributes on the task once it lands there.
Not currently possible. A cool idea IMO, I haven’t seen this request before that I can recall.
Requested here; you can add your vote!
Not sure I follow here - there’s already a “due date set” trigger. Perhaps you mean a trigger that would fire if any date is set in a custom date field? That’s not currently possible. if that’s what you’re asking about/wanting.
Not sure what this means, sorry. (I can make some guesses but that’s not very useful…)
Requested here; you can add your vote!
Requested here and here; you can add your vote!
That’s a broad topic. There are some calculations currently available in parts of Asana, and there are some forum threads requesting other types of calculations.
One final comment…
Asana doesn’t publish a public roadmap or comment on unreleased features, so it’s not possible to know if something is coming until it’s announced.