As (maybe) previously mentioned, a player enters a skirmish with a single squad. A squad consists of a set of 'primary units', which use a class-based advancement system, and are led by a single commander. The commander is responsible for managing unit resources, morale, and formations, and is intended to be the director of combat. He is not necessarily a combative unit, but with a small squad the commander will necessarily become part of the action.
The primary goal, from the design perspective, of the commander, is to be a focal point for group management and development, and provide an advancement and customization path for different players. The commander is the player's avatar in skirmish, and perhaps also in the exploration and development modes of the game. The commander is where the player decides how he wants to play.
So let's look at how the commander develops. That's been the primary focus of our design, since implementation of formations and combat implications of command are not yet implemented.
Primary units are numerous, and therefore use a 'simple' development scheme, which requires only very rare user interaction. Primaries can change their current class at any time, but new ranks of the class are automatic, and new class availability is relatively rare. Commanders are single, and warrant more interesting decision making. We've decided to go with a skillpoint based system, where at set quantities of experience, a commander will gain a skillpoint, to be used whenever and however the commander wishes.
Commanders purchase skills from 1 of 3 categories. The first category is called the Resource tree, and covers skills that manipulate resources, equipment, and often morale. The second is called Tactics, and covers actions and maneuvers. Tactics may grant new abilities or buffs to the commander and/or his squad. The last category is called Command, and governs the leadership of the commander. Command may grant new formation slots, new maneuvers, or introduce a bias towards defending, or perhaps improve the commander's ability in certain situations, for example, being outnumbered, or defending an outpost.
Each category is arranged in into a set of skill 'Cells'. A cell is like a small skill tree, broken into 3 conceptual areas. The first row is the entry point of a cell, and there is only a single skill to be learned. Learning this skill grants access to the cell. Rows 2, 3, and 4 are other skills, and may have interdependencies, or not. Typically we expect to have 2 to 3 options per cell row. Requirements to advance down a tree are not set in stone yet (or maybe I just do not remember?). The last row, row 5, is the advancement row. Skills in row 5 match the row 1, access skills, of a new cell. When this is taken the new cell is unlocked. Furthermore, access skills are restricted. It is intended that selecting which cell to advance into is an important decision, and maps to how the commander is developing. The intent is that a commander uses skill points to develop within a cell, then occasionally picks a new cell to advance into.
The method of restriction is still relatively undecided, though several possibilities are under consideration. A simple option is to make all row-5 skills exclusive, so only 1 in any cell may be taken. This prevents breadth-first development, and forces a 'downward' momentum, which may force specialization, depending on cell structure. The next possibility considered would be to introduce a new type of skill point, rarely granted, which may only be used to select a new access skill, but may be used on any available access cell when granted. This allows more freedom at the expense of some simplicity.
Now, each category of skills (Resource, Tactics, Command) is not weighted the same, nor will they become available at the same time. At the moment I'm considering having Tactics be available from the onset, introducing Command later, and adding in Resource last. Introducing new concepts to players in a controlled way has its advantages. Hmm, perhaps we should actually write down the 'Player training experience' sometime....
To implement the separation of categories, we may introduce 3 types of skillpoints. Each is granted at different XP values. Say tactics points are granted every 200 XP, starting at 200. We could introduce Command points every 400 XP, starting at 2000, and easily control the rate of skill gain.
For reference, since it hasn't really been discussed, Kol is been in charge of Primary Unit development, and Eirikr is in charge of Commander design. We all discuss the possibilities of course. I'm in charge of implementation, so they are both doing more of that themselves as time goes on. Maybe I'll pester them into posting sometime too.