Hi, Graeme:
I see the Chieftain series as the ancient version, with Overlord introducing slightly more modern "weapons" and a larger [and in that sense more modern] army. These games are deliberately very chess-like. WarGame approaches the idea of a chess-wargame hybrid from the other direction, keeping only the deterministic captures of chess and its variants.
I expect this game to be a "proof of concept" sort of thing. Oddly, I see a more "ancient-style" game having longer movement factors as a possibility, to give at least a few/some pieces a ranged attack.
I was thinking of using hexes, but I decided to stick with squares to start. I'm currently looking at a few pieces on a 20x40 board, but I'd like to extend the long side to 45 or 50 if I can and still have a "1-screen" board that's reasonably visible.
I thought of a points system, and hidden setups - I have looked at 4x5 blocks of squares and pieces that could be bought as a whole - but I will probably offer that as an option, and go with a reversed setup of some sort with identical armies in exactly corresponding positions.
I still have to put in line-of-sight rules, but they are easy and obvious. The leaders are what I do not have down at all yet. They pose many difficulties. I've experimented with various sorts of leaders, but I don't know quite where to take these leaders. I was thinking of working up to the chain of command gradually, but envisioned 3, maybe 4, levels.
Now, if 3 levels, there'd be 2 top leaders, who would mutually activate each other as well as their subordinates. With 4 levels, it is not necessary that the top leader be very mobile. I could see a command post that moved 1, and used an activation up to do so. That would pin it down pretty well, but still give some flexibility.
I'm still not sure quite how many pieces each leader can activate.And with chain of command rules, I will have 2 kinds of activation, active and passive. Passive is just being within range of a higher-level leader, and it allows a leader to become activated itself. Active activation [really p-poor term, that] is what occurs in chief [and chesimals] to allow a piece to actually move in a turn. Ranges for the 2 types may be different for any given leader. I'm thinking the lowest-level leaders might move 2 pieces and themselves, or thereabouts. Not any good ideas about higher-level leaders, though I think any leader should at least be able to activate 1 piece to move every turn.
There's one more consideration, and that's the percentage of the army that moves each turn. At start, for FIDE it's 1 in 16. For the chief series, at start, it's 1 in 8. I don't know that I'd want to be moving more than 1/6th of my army at start, to keep some semblance of order and calculability in the game. Obviously, as pieces are lost, and leaders are preserved, the fraction of the army that moves each turn goes up. You're pretty much to the endgame when you're moving 1/3 of your army each turn, because if you are moving 1/2 of your army each turn, each non-leader piece has its own leader to move it, and after that, the leaders are coming into the front lines.
That's what I'm looking at so far. This is as far as I've gotten with a preset - not very:
[http://play.chessvariants.org/pbm/play.php?game%3DWarGame+1%26settings%3DWargame1]
Joe