Caeleddin said:
You don't. I do.....
Take your pick.
>Wizards with Cha, Wis and Str 8.
I don't like to have low Wis or low Con. A failed fort or will save often kills a character or otherwise incapacitated. Also, wis is a key ability for Spot and Listen. Remember Wizard can still take those skills as cross-class skills. It helps avoiding surprise round. I can sacrifice Dex for an arcane caster. But not Wis. While I agree with that Con is more important, low wis is no good.
>Fighters with Dex, Cha and Int 8.
Fighter with low dex and low int. If that is a fighter, he is barred from so many feats. Now he can't enjoy his bonus feats that much. If he is either Barbarian or Ranger, he is simply in trouble with poor Dex. He is also barred from some nice prestige classes as he can't take appropriate skill ranks and feats.
>Rogues with Cha, Str and Int 8.
Rogue with low Int is inconvenient. Amount of skill points are important. Also, Search and Disable Device (both int-based) are so important for party survival (or case solving). Also, a Rogue with Str of 8 often meets a trouble of encumbrance. He must keep light load to be effective.
Of course, some player may love simpler character. But not all the players do the same. And not that taking three 8s is the best way (or only way) to go.