"Focus"

x4E introduced "Stances," a tactical move that sets up an attribute for the length of an encounter. So basically, you could sacrifice speed for defense, or increase your damage output, etc.

In AD&D, some characters had "operational stances." By this, I mean that they had choices that could change their basic derived statistics but those choices generally could not be exercised in combat. For example, take a dexterous fighter.

He can choose between Leather Armor and his Chain Mail.
- LEATHER:
PROS: Retain reaction adjustment to surprise, better init with missile weapons, better surprise if he's an elf or halfling, could be slept in
CONS: Reduced AC
- CHAIN:
PROS: Better AC
CONS: Reduced speed, lose DEX bonuses

To swap out your armor was usually something done out of combat. Hence, it being an operational choice, not a tactical one.

Why not do something intentional but not linked to equipment so all characters can choose?

- AMBUSH: Surprise 4/6, +2 initiative
- LOOKOUT: Perceive 4/6, +2 on OAs
- MOBILITY: Succeed on mobility maneuvers 4/6, +2 speed
- FORTITUDE: Recover 4/6 (saves, recovering health overnight, etc), +2 stones ENC capacity
- LEAD: Inspire & Command 4/6, +2 morale

Each character can select their status. It takes a Turn normally to change Focus, or you can use my order of magnitude check described elsewhere to do it tactically over a few rounds. Additionally, each character has one status that is naturally "3/6" -- all others being "2/6." So, a thief might be Ambush 3/6. Thus, the thief, if scouting, can AMBUSH 3/6 and PERCEIVE 4/6. It makes him a better scout than a fighter or cleric, but the fighter and cleric can still tag along if they set their focus on AMBUSH.