"This assumes unconditional surrender. Had we agreed up front to conditional surrender (e.g. letting the Japanese keep the emperor) both the mass cooking of babies and little old ladies and an invasion could have been avoided."
If I remember correctly, the survival of the Emperor was not the only issue in a conditional surrender. Most of the government would have been left intact. We also picked intelligence that the conditional surrender that was offered was a stall for more time.
Dropping the bomb was a good decision.
If it was stall, it interesting that Truman, overruled his pro-FDR advisors, and in the end agreed to conditional surrender e.g. keeping the emperor. The Japanese then stopped stalling (which had continued even after the bomb) and complied.....but only after Truman agreed to that condition. Had Franklin D. "Unconditional Surrender" Roosevelt still been president in August, the war would have continued to drag on even after dropping the bomb. Truman, at least, finally realized that the continued demand for Unconditional Surrnder was a foolish waste of lives.