OK, so the system's dead-simple. There is no advancement. What's the appeal? What's the angle? Why should anyone give a crap?
The meat and interest of the game mechanically will be in the character creation.
It's a lifepath system.
You start with a 16 year old, randomly determine the character's starting situation, and get rolling.
I think of it as somewhere in the middle of Burning Wheel, Warhammer 1e, and Traveller, but involved to the point of being its own 10-15min solo mini-game. Deep enough to be able to make 100 characters and have none of them come up the same or even similar.
Each bit along the path takes d6 years, gives a random selection of skills relevant to the "profession" rolled, and then gives a random exit path.
You can stop at any time and say "OK, this is my character at the start of play." At some point you need to because characters can die (you do NOT want to go to Jamestown) or get so old they start taking penalties (defeating the only point of continuing on).
The system will both highlight real-world locations and events while at the same time making sure people know that it's not at all necessary to be a history freak to get into the game or setting... because each step is a random amount of time and you don't know ahead of time how old the character will be, things can pop up out of order. "Oh, I was a founding Plymouth settler (1620), then I went to become involved in the Gunpowder Plot (1605), then I helped repel the Spanish Armada (1588)! And I start play at 30 years old!"
So character creation will tell the story of a life but will also need some interpretation to completely come out straight.
Paths will not just be military or other "adventuring" kind of things... you might be a farmer or innkeeper or what have you - but even so if it's in one place it will have different benefits, risks, and exit paths than other places. It's going to be all over the place... and not necessarily pleasant places. If your character was a back alley criminal at some point, chances are that character will have done some truly awful things. Your character might have been a slaver. Or a slave.
(the character creation for the core game will keep a European focus or else the whole thing goes completely out of control as far as options and page count... different areas might have lifepaths done as separate things so you can start in the Ottoman Empire, as a native in the Americas, in Japan, or what have you, but that's a secondary concern because it can't be done all at once and one should start off where one is most comfortable and familiar)
One benefit/drawback of this approach is that you do need something for all these "non-adventuring" paths to be good at. They shouldn't be wasted years. "Oh shit, I'm a farmer for three years. Worthless!" That's bad. And when politics, the clergy, business, and academics are possible paths in the system, they all need some sort of benefit. So that path that brings a player to potentially be a Galileo type genius or a Shakespeare-level playwright? That needs skills to reflect the knowledge that brings and that needs rules descriptions for things those skills do in play.
So that inflates the skill list. Which doesn't trip the traditional problems of a large skill list in a game, because the players are taking them as they come and not spending time choosing them, and people who don't have those skills can still attempt to do the things the skills aid. And the character sheet, which starts as a blank, only has those skills added to it which come up in the lifepaths.
The end result is supposed to be a motley crew of misfits that, at the time play begins, band together to explore, experience, and perhaps even fight the unknown and dreadful forces pushing in at the edges of reality.
