It's interesting to read about how the hardcore USAF fighter mafia types slowly made their way to the pentagon through their careers and their experience and uncompromising "not a pound for air to ground" led to the development of the F-15. The F-15c is probably the purest most successful combat fighter ever.
Take the same basic airframe, slap on some conformal fuel tanks, add an EWO in back to run the weapons systems, add some sensors, increase payload capabilities and you have the F15e. Also extremely good at being a jack of all trade strike fighter.
The fact of the matter is for any sort of high intensity complex operation or maneuvers you need an onboard pilot to maintain complete situational awareness.
And for what its worth the A10 is the purest killing machine to fulfil the purpose it was intended to do. The entire plane is built around its 30mm cannon, designed to survive damage, high manuverabilty at low speeds, operate on unimproved fields, etc... its awesome at what it does.