I personally don't think that Weapon Finesse is a very good idea for a feat as it has been discussed. The problem I see with it is that the developers of this game have taken great pains to balance the classes against one another and to also balance the importance of the different stats to each Character.
Simply put, this idea of being able to spend one feat to be able to substitute Dexterity for Strength in your Melee Basic Attacks totally makes Strength a next to useless stat for most Rogue builds. With this feat, why would I ever develop my Strength beyond a token level as a Rogue? I could very easily nerf a character by pumping up my Dexterity because I now get an awesome defense bonus, and yet still reap the benefit of an increased attack value as well. What I am basically trying to say is that there is no real tradeoff here. However, there is a very easy way to acheive this tradeoff.
Basically, you allow the feat to only affect ability to hit, and keep the modifier for damage based on Strength. As for how this would be written up, maybe something like this:
Nimble Strike
Prerequisites: Dex 14,
Benefit: This Character is able to use their Dexterity modifier in place of their Strength modifier to hit when striking with any Light Blade. This strike would do the normal stated damage for the power or attack used as listed in the power's description, (ie. if the power or ability reads that it would deal [1W]+Strength, this would still be the damage for that power or ability even though Dex was substituted for STR in the attack roll).
What this would do is to expand this feat out to being a truly useful feat for the dexterity based Martial Character, but still require you to rely on a secondary stat in order to acheive any real bonus to damage, unless you are of course using a power or ability that dealt damage based on your dexterity.
ideas?
Dallas Honeycutt