It was a simple matter of Japanese leadership clearly raising the white flag, and they didn't do it.
So, no, I don't think any subtle intelligence was ignored or missed in the decision to drop the bomb, and that decision was determined just as history has represented.
Anyway, Okinawa, the last battle before the planned invasion of the Japanese mainland, saw the most American casualties of the Pacific Theater to determined Japanese defenders, many of whom were new and not well trained, which just about proved beyond doubt that whatever the morale of the Japanese, they would fight to the death in defense of the mainland.
There were about 155,000 Japanese defenders on Okinawa. Battle casualties amounted to about 72,000 American and 100,000 Japanese, which is getting pretty close to parity. The battle lasted about 80 days. That translates, simply enough, into very tough, grim going on the mainland.
Operation Downfall, the Allied plan for post-Okinawa final invasion of Japan, was projected to continue well into 1946.
https://en.wikipedia.org/wiki/Operation_Downfall