If I might weigh in here briefly.. You appear to be spending a rather large amount of effort defining a rather large amount of things. Also, since what players can and cant do is still a bit murky, your players may be concerned about what they can and cannot do. Leading to more questions and answers here in the OOC thread, and less turn posts getting done.
This is really more of a beta, hell alpha play through, I want all these questions being asked, it helps me think since my best ideas come from when I'm rambling, and I can't ramble to myself, that would be crazy.
You need to scale things back. By placing limitations on the capabilities of people, you reduce the amount of questions they can ask. In a system like this I'd likely define things in terms of Age (Stone, Bronze, so on up) so players are reasonably assumed to have the capacities of their age. So as to do away with pesky research needing to be defined. In addition by limiting things due to age, you limit some chunks of territorial definition until later (Think revealing resources in the Civilization games).
Tech wise I never plan on this game getting up to gunpowder, it's pretty much medieval but each kingdom starts off small. I don't want to have to keep track of everyone's tech, in the next version to save time, stone/ore/gem resources that start off in your area will already be defined, simply put, I'm not going to do ages, since player characters do age and die, and it'd suck to be stuck in the stone age for 20 years because we play turns weekly/monthly.
I'd also scale back hero capacity, but strengthen the value of heroes. Everyone, right now, is rushing buildings to grant more heroes, so they can get more actions happening for their side. More actions -> More progress -> Greater ability to subjugate everyone. By making buildings that grant hero slots harder to obtain, you can prevent people from endeavoring to game the system in this way.
Maybe break it up, have the heroes do completely different things. Slay great monsters for prestige, explore the lands, acquire wealth for their nations, defeat small-medium threats. Have the leaders administrate what gets built where, founding new cities.. Empire type things.
---
On the other hand, Loving the definition work. It makes the world feel more varied. And I like the way you've simplified resource collection (and thusly tracking).
Heroes are going to be nerfed yes, they probably won't be able to use their influence for anything until they actually obtain a position of power (mayor, priest, king, lord, general, etc) but they'd be limited to influencing only their town, religious followers, kingdoms, fiefs, soldiers under their command. Not to mention the soon to be coming skill system will define heroes much more then being the leader's lackey. They'll probably also have more chances to be independent, such as purchasing and trading goods between nations, being mercenary, etc. I'll probably also add npc threats as well. Not sure how I'm gonna handle heroes joining, but one guaranteed way would be current players having children, seeing as when they reach 16 they become playable, their skills will be based on how they were raised though, and not by the new player's choice.
Just a minor addition: going by the game's current ruleset having certain resources only be revealed from a certain age onwards would turn out fairly problematic; developing a tile automatically destroys all of its old features, hence, players might have severely curbed their access to late age resources in the process of automatizing their economy. On ther hand, since said advanced resources would probably be of mineral nature, one could make a case for ores not to be affected by a tile's development, more likely than not altogether solving the issue.
Stone/ore/gems aren't destroyed when places are clear cut (since they aren't plants), if flat lands had ore, you could build 2 farms, a pasture, and a mine on the same spot.
Also season's are gonna be taken seriously, so when it's winter time, you better hope you had food stored up, or at least some livestock that can supply you. Lots of foods go bad now, still working on that mechanic though.