This suggestion is a tough one to implement because it would require a lot of new animations to make it work, but I feel it would a wonderful addition for those of us that are left-handed (I am, and I would love to have my character left-handed as well) and enjoy playing as left-handed (considering that most games only feature right-handed characters), or for those that would like to RP with left-handed characters. This would include tool usage, combat, animations, etc.
This would also add diversity to the combat system because NPCs could be left-handed as well, if you so desired; there certainly were left-handed combatants in the world, why aren’t there in this world? (Aside from the obvious answer of development costs versus usage and practicality.) Just a thought.