That's pretty much what this system does. You can combine traits in any way you want. There are some traits you can't pick together, for example being more afraid of abominations and being less afraid of abominations can't be picked together. You can take only one, which means there is less room for conflict. You can still take more than one personality trait however. You can be a psychopath who is good at haggling, enjoys company of other people and is a lazy worker. The system makes it very easy to check what traits the player has, so making unique dialogue for certain situations will be easy.
By the way, what dialogue is different for tomboy? I completely forgot about it.