I must admit, I too felt there was a bit of a dissonance, between Wyll being the "Blade Of Frontiers" story-wise but not quite having the Dexterity for being a rapier duelist, as far as the mechanism of Ability Scores is concerned.
It's somewhat similar to Shadowheart being a Trickster-domain Cleric with the Urchin background, and having no Dexterity to go with the Stealth and Sleight Of Hand one would have expected her to be good at. I heard she was changed in Patch 3, to have Ability Scores more in agreement with her story though.
