Attribute

I'm done with the concept, so here are the more detailed opinion. To start of first, I find it too simplifying to reduce a human into 4 to 6 attributes, it feels... demeaning. Not only that, the lack of interdependence between them presents the characters as 'parts of a machine'. Actually, it's worse than that because every part of a machine relies on the other parts to perform.

What I like to see.. is that the attributes have a direct link to complement and synergize each other.
First is to deal with the most basic of them:

Strength The physical part of the character, symbolizing its capability to carry objects such as weapons, armors, backpacks etc. It is measures the physical damage it is able to inflict.

Porting it over to gaming terms,
1. A main over-encompassing factor in deciding physical damage.

Intelligence The mind power, most used to describe the capacity to understand magic. However, it should be more than that. With a better brain, would he not learn skills with ease? With a quick thinking mind, would she not be able to decide the best course of action?

Thus,
1. The main factor in deciding magical damage.
2. Faster growth in rising up the skill ladder. (Check skill concept)

Constitution The body. The summation of the muscles, joints and bones. In other words, capacity.

In that regards,
1. Measurement for health points.
2. Measurement for mana points. (In the view that casting magic hurts the body.)

Dexterity The ability to utilize an item. For example, how Bruce Lee is able to keep the nunchaku revolving around his body. More specifically, the sharpness in the utilization. Many games tried to symbolize that through critical rates, which in my opinion, an inappropriate word for its effects.
Porting,
1. A secondary factor in deciding physical damage.
2. Opportunity Strike - is the better word. The character is able to take advantage of 'openings', to strike for additional damage. Critical (point) strike, would be the better word to describe acts from martial training.
3. A factor in increasing attack speed.

Then to more uncommon attributes.

Vitality I believe this should be defined separately from Constitution. Whenever someone mentions that a person have great vitality, it usually refers to their capacity to survive over the long term.

1. Affects regeneration. (HP, MP etc)

Stamina Instead, this word refers to the capacity a person have in the short term before he gets exhausted.

1. A stamina bar. (To substitute cool down times.)

Agility Whereas Dexterity affects the speed and mastery over a weapon, Agility is about the speed of the body.

1. Quicker walk movements.
2. A factor in attack speed.

Wisdom Heals and buffs are a major factor in team play. As such, it is appropriate to allocate an attribute for that. Care must be taken that any party it does not force a healer to have max Wisdom.

1. Increases heals and buffs abilities and range.
2. Increases holy/divine powers.

Luck It is hard to quantify luck in real life, but there is no denying it either. Luck is basically the unexpected things, be it good or bad.

1. Separate count for hit, dodge, block, critical rate etc.