
But. As you mention, one needs to be very careful in designing the themes to avoid having one or a few obvious army choices. At the same time, one needs to keep the theme from being too obscure in order to make sure that no players are excluded simply due to a lack of available figures. And, just as important, there is the need to make sure that the themes are not all the same in a meta-sense (all foot slogs, or all shooty cav, etc.) I know I am largely repeating what has already been posted; I do it by way of emphasis.
To take your "Dawn of Chivalry" proposal, I wonder whether the clever choice isn't to figure out which list give the most armored offensive spear, or better still, combination of foot and lancers dismounting as armored sp. Normans spring quickly to mind. In a regular Period 3 the armored spear guys might not be so obvious a choice.
Marc