is Graviton theory throwing relativity out the window?

Answer 1

No. Any "graviton" theory must reproduce the results of General Relativity, at least in the "weak field" cases. "Weak field" here means scales bigger than roughly the diameter of a proton.

The whole idea behind gravitons is to try to make General Relativity consistent with the physics of particles. This involves treating General Relativity as a "field theory" in the particle- or string-theory sense. General Relativity has passed all observational tests invented for it, and is therefore "true" in the weak-field approximation. Newtonian gravity is not "out the window", even though it was superceded by General Relativity, because it is a correct (and easily-applied) approximation to most situations involving gravity. Similarly General Relativity will continue to be used for all "weak field" cases, even after it is superceded by a theory that better explains quantum gravity.

I might add that the idea of gravitons is now decades-old. It is entirely possible that the theory that supercedes General Relativity will not include gravitons, but rather some other mathematical entity. Gravitons are creatures of "field theory", and field theory begins with the idea that time and space are connected by an underived constant "c", the speed of light. A "theory of everything" should explain why this so, and might not be a field theory at all.

Answer 2

Any relativistic effects - from Dr. Eddington's observations forward - would have to be described by any theory that wants to replace relativity. It would be a case of relativity being restated and expanded, not thrown out the window. That being said, graviton theory does indeed sound whack.

Answer 3

no. graviton theory is completely compatible General Relativity.

What is not compatible with General Relativity, is a quantum gravitational theory (still to be developed, and when this is done, it will have to be compatible with General Relativity at larger scale).

Answer 4

No