Should Weapon Finesse cost a feat?

[Eldariel]

Further penalizing DEX builds is kinda mean in a fantasy game. As for DEX to damage, personally I leave it as is, but have been thinking on what to do with WFinesse and Shadowblade for some time.

Honestly, making Weapon Finesse grant Dex to damage is fine. Then Dex-focus has a cost but not such a massive cost it has now. And Str-focus has so many natural bonuses when it comes to melee combat that it's fine really (tripping, two-handed weapons, power attacks, etc.).