[CUnknown]

I love your idea about armies needing decreased/increased support $ per turn if in a Productivity/Sloth dominion (maybe 10, 20, and 30%?) However, I don't think the code can handle this, especially if mages wouldn't be affected by it (and they shouldn't be).

Perhaps a simpler idea would be to just increase the amount of resources/cash it gives, like the last thing you said.

Another idea might be to increase/decrease castle construction time. If it was 1 turn per level (minimum 1 turn of course), that would be huge! A 3-production nation would be cranking out expensive castles instantly, whereas a 3-sloth nation would never be able to build castles anywhere near the front lines.. a 6-7 turn construction time would turn a risky move into basically something that is not worth even trying.

Or a 10% per level increase/decrease in all building (castle, temple, lab) costs? That would be a nice bonus as well.