So really, this is entirely up to your DM.The character may wish for greater effects than these, but doing so is dangerous. Such a wish gives the opportunity to fulfill the character's request without fulfilling it completely. (The wish may pervert the character's intent into a literal but undesirable fulfillment or only a partial fulfillment.)
FireLance said:you get about 20,000 gp for a basic feat, which is within the guidelines for a Wish. So, I would allow a Wish to grant a feat that the character already met the prerequisites for.
hong said:I'd say it's okay, providing you already met the prereqs, and you hadn't already used a wish for this purpose. Ie, you can only get one extra feat this way.