I can't believe this is even being debated. Just for balance, Strength has to have the most important role in damage. It's debatable whether the default for "to hit" with light weapons should be Strength or Dexterity. If I'd designed it, I might have made "to hit" by default Dexterity, but with a feat, the reverse of Weapon Finesse, it could become Strength; though with heavy weapons the "to hit" would be Strength based.
Still, it's one feat to get "to hit" with light weapons based on Dexterity, so it's not a big deal.
But letting Dexterity do everything in combat is pretty ridiculous. The tropes referred to about smaller weaker guys outmaneuvering bigger guys generally involve outsmarting them.
Bringing up 4e as if it's a good thing makes little sense to me on a PF board, because don't we play PF rather than 4e because we wanted further development but don't like the 4e changes?
I'd support as suggested a feat allowing Dexterity to increase critical hit chances, but it should be on the confirmation roll, stacking with Critical Focus and Weapon Finesse, which might add the Dex modifier to critical confirmation rolls, reflecting precision. Adding to critical threat ranges runs too much risk of being overpowered, but making confirmation easier seems reasonable.