I just thought I'd add a couple of comments to yours and everyone else's thoughts on "1644". I think they're a great set of rules. It's been a while since I used them, but when I read Londonjock's description of the siege of Julich, I dug out my notes of a few amendments we'd tried in some games a few years back. (We used them in a Grand Alliance game for which we were trying out "1644" ("1694"??), but the idea would work also for ECW or TYW).
One of the things I really like about the rules is their focus on the command status of each unit, which deteriorates as the battle progresses, subject to units being reformed. One thing which was left out, perhaps to avoid slowing down the the game, was any command limitations as regards the generals of the respective forces.
Without wanting to alter the rules too, we tried to add some characteristics for generals into the mix, designating the generals of each side as being either Professional, Rash or Cautious (legacies of Mr George Gush's WRG 2nd Edition rules of happy memory!!).
A Professional general was, well, professional and could place charge and reform intention counters in the Intention Phase pretty much as mentioned in the rules on page 8.
A Rash general was required to place at least two charge markers each move on units which were within charge range of an enemy and which were capable of charging. A reform counter could only be placed by the Rash general to the extent that at least one charge intention counter had been placed by the general in the same Intention Phase.
A Cautious general could place a maximum of two charge intention markers each turn. However, once the general had placed his first charge intention marker in the Intention Phase, he would loose the potential to place a second charge marker if his army contained a unit with disrupted or lost command – the logic behind this, from what I can recall, was that the Cautious general would prioritise reforming the disordered unit in preference to pressing forward an attack.
Well, that was it! Nothing earth shattering, but I remember they provided a bit of extra entertainment and made the battles quite a bit more difficult to control.
We also tried a game when rash generals were required to place a charge marker on a unit within charge range of any enemy unit which had just rallied (as on page 20 of the rules) in the last phase of the previous move. I think this proved a step too far and we didn't repeat it. My memory's a bit hazy, but I think we ended up with half the French Horse routing some newly-rallied Dutch militia battalions off the table, and the French foot subsequently getting stomped on by the rest of the Alliance while the chevaliers were trying to get back onto the table!
Now that would be an interesting topic….."Wargaming rules which I thought were a good idea but didn't quite work"!!
All the best,