There's two sides to something like a stat: penalties for having it low, and rewards for having it not-low. They'll lead to different behaviors with respect to dump-statting. I would say that low Con is penalized (everyone needs resilience against attack to be functional), but low Str is not except in the case of carrying capacity, since if you're a wizard, having low melee damage is basically ignorable.
For example, take Charisma.
RP penalty: NPCs tend to harass low-charisma characters regardless of what they do.
Mechanical penalty: Charisma is used as a defense against some forms of attack that are relatively common, and so low Charisma means you get knocked out/killed/etc more often.
RP reward: NPCs spontaneously tend to show up and do things for any high Charisma characters in the party. High Charisma means you start as nobility and gain various contacts and priveleges from it.
Mechanical reward: You can use Charisma checks to shape morphic planes. You can use Charisma as a bonus to hit/damage/what-have-you. You gain bonus spells based on Charisma.
Rewards will tend to encourage bipolar stat distributions in the party - the people who synergize well with the rewards will have high or at least above average values, while the people who don't care about those rewards will have low values. Penalties will tend to encourage across-the-board average stats to avoid weak points.
For example, take Charisma.
RP penalty: NPCs tend to harass low-charisma characters regardless of what they do.
Mechanical penalty: Charisma is used as a defense against some forms of attack that are relatively common, and so low Charisma means you get knocked out/killed/etc more often.
RP reward: NPCs spontaneously tend to show up and do things for any high Charisma characters in the party. High Charisma means you start as nobility and gain various contacts and priveleges from it.
Mechanical reward: You can use Charisma checks to shape morphic planes. You can use Charisma as a bonus to hit/damage/what-have-you. You gain bonus spells based on Charisma.
Rewards will tend to encourage bipolar stat distributions in the party - the people who synergize well with the rewards will have high or at least above average values, while the people who don't care about those rewards will have low values. Penalties will tend to encourage across-the-board average stats to avoid weak points.