It is reasonable to abstract Intellect into damage, since Strength would logically affect melee attacks only, but there should still be some use for Strength in damage calculation. I have thought about the kinetic aspect of Strength once more, and it occurred to me that Strength also translates into
explosive speed. This way even the spell-casting classes have definite utility for having invested in physical power.
Let's assume that the PoE character system has scale 1-10 point buy for attributes, with 5 being the baseline. Strength should signify the speed bonus the characters have when they enter combat, and now Constitution would also affect how long the character is able to uphold his state of adrenaline rush.
Code:
If STR > 5, PC's initial speed is multiplied via formula x1.(STR-5)
If STR = 5, no bonus nor malus.
If STR < 5, PC's speed baseline is actually x0.(STR+5), so the PC begins with regular 1x speed that slows down.
If CON > 5, PC's initial speed slows down -0.(11-CON), and PC will face a winding penalty round if his speed doesn't baseline evenly. For example, a STR 10 CON 7 character follows round speeds x1.5 => x1.1 => x1.1 (*another round) => x0.7 (winding) => x1.0
If CON = 5, PC always baselines without winding after the initial round.
If CON < 5, before returning back to baseline speed, the PC suffers an extra winding period of -0.1 for 5-CON rounds.
*PC gains a bonus speedy round whenever he is only 0.1 multiplier away from his baseline and then is set to have a winding penalty equal or greater than 0.3
The balancing might be less than ideal, but I think it would be very interesting to consider the tradesoffs whether to utilize front loaded berserkers that deal less damage, but disrupt enemy initiative, or trying to make a team that hits hard, but initially has difficulty to stay up with the opponents. You can imagine the pain if your group faces hostile spell-casters with high Strength and Constitution, since they may be able to outcast your mages for a good while.