There's video interview with
Takahiro Tomohiro Noguchi on DC Watch about the GR III. Noguchi-san is someone very closely associated with the GR. He runs the GR blog site. I saw him interviewed about Ricoh cameras before the Pentax acquisition, so I'm sure he is from the Ricoh side originally.
For the most part it's just what we've heard before. He stresses hat this not a minor change but the whole camera is redesigned from the ground up. The interviewer comments on how the Gas all look the same since 1993. Nogichi-san answers that every time they go through a process of considering other designs, but when they think about the use of the camera, they come back to a similar design. He does say that users are going to feel more of a change when they operate it.
What I found interesting were his comments about demand for the camera. He said that over the years smartphones have taken sales away from compact cameras, but that the GR is stable. It has not been affected at all. He also said that the camera is particularly popular in Asia and China in particular.
Here's the video for anyone who can understand.