Attributes and Ability Scores

I have been looking for a good system to use when running my megadungeon. The current players that I have available are mostly familiar with the storyteller system, but the storyteller system does not really handle tactical combat very well, and I want the option to have tactical combat for set piece battles, or perhaps for every battle. In a way I'm working backwards because I already have an idea for the final fight with the Big Bad in my head.

The core of a character, at least mechanically, is either the attribute scores or the skills. After looking at several different systems it appears that the most popular systems either use three, six, or nine attributes. There were some odd outliers, but I am not personally familiar with them and they appeared wonky with sometimes overly specific attributes.

In Dungeons & Dragons, and its' various off-shoots, the standard characteristics for a normal human are generated by rolling 3 six-sided dice, resulting in a range of 3-18, with an average score of 10.5. This makes most event evaluation relatively easy, requiring either a 3d6 or 1d20 dice rolls. The set of attributes is compact, useful and easy for most players to understand.

The physical attributes are Strength, Dexterity, and Constitution, while the mental attributes are Intelligence, Wisdom, and Charisma. The creature and magic scaling issue is handled, somewhat, by  offloading a variety of other effects to an artificial parameter known as the character level, or number of hit dice.

Several other systems use a three attribute system, sometimes referred to as mind/body/soul but more often physical/mental/social or power/finesse/resistance. These systems often involve combining the attributes with various skills to either get a modifier or a larger dice-pool.

I am torn between two different attribute systems: a system with three attributes and a system with nine attributes. A three attribute system lends itself to easy character (and NPC) construction. A nine attribute system that is a combination of power/finesse/resistance and physical/mental/social gives a specific score to deal with different situations. A nine attribute system also allows me to separate the capacity to deal with stress and the chances that you will actually become stressed.

Tentative attribute system

(power/physical) strength:
Strength is a measure of bodily power, athletic training, and raw physical force. It adds to attack and damage rolls when using a strength-based weapon. Strength also determines carrying capacity and is used when performing actions such as forcing open doors or hanging onto a speeding wagon while you are being dragged behind it.

(finesse/physical) dexterity:
Dexterity measures physical agility, balance, and poise. It adds to attack and damage rolls when using a dexterity-based weapon. Dexterity also modifies your chance to be hit and is used when performing actions such as keeping a trap from functioning or wriggling free of bonds.

(resistance/physical) constitution:
Constitution is a measure of health and durability. It adds to your health pool. Constitution also modifies your chance to become fatigued and is used when performing actions such as holding your breath for an extended period or drinking an entire stein of ale in one go.

(power/mental) intelligence:
Intelligence measures the ability to recall information and to reason. It adds to the number of languages you know and is used when performing actions such as communicating with a creature without words or estimating the value of a precious item. Intelligence also forms the basis for the magic ability of some classes.

(finesse/mental) wits:
Wits measures quickness of thinking and the ability to perceive the world around you. It modifies your initiative roll and is used when performing actions such as determining how to cause part of a tunnel to collapse or figuring out the direction to a source of moving air while underground.

(resistance/mental) resolve:
Resolve measures a character's strength of will and intellectual focus. It adds to your capacity to handle stress and is used when performing actions such as resisting supernatural mental effects or standing your ground in the face of great danger. Resolve also forms the basis for the magic ability of some classes.

(power/social) presence:
Presence measures eloquence and appearance, bearing and stature. It adds to the base morale of your hirelings and is used when performing actions such as attempting to intimidate someone through overt threats or trying to convince a gang of street thugs to back down from a confrontation. Presence also forms the basis for the magic ability of some classes.

(finesse/social) manipulation:
Manipulation is the tool of trade. It measures your personal charm and the capacity to play upon the desires of others. It modifies your ability to reduce the stress of others during rest periods and is used when performing actions such as finding the best person to talk to for rumors or blending into a crowd. Manipulation also forms the basis for the magic ability of some classes.

(resistance/social) composure:
Composure measures your capacity to remain calm and appear unfazed in threatening situations. Composure reduces your chances to become stressed and is used when performing actions such as rallying hirelings whose morale has been broken or looking unspeakable horror in the eye. Composure also forms the basis for the magic ability of some classes.