It is true, why don't they do that. While some parts of Japan have pedestrian-vehicle separated traffic signals, I think that could also be a good countermeasure. 

 The actual optimization is roundabouts.  

 Sure, but that's a physical hard fork. Changing the programming of the lights is a soft(ware) fork. 😏 

 Preach!  

 Is that the “gentlemen start your engines” light? 

 Seems like it could cause confusion in certain situations if yellow precedes both the stop and the go 

 It doesn’t. The other light turns red before. 

 OK, so there's one light that changes color, you're at a sidestreet intersection with a stop sign, turn right, and see a yellow light. Do you assume turning red or green next? 

 Yellow means go.  

 This. 👆 

 In some countries  orange (quite similar to yellow) means you can pass but you don't have priority, that can lead to confusion IMO 

 It could be red and Orange so orange meaning stays clear. Then you have An issue though if the red light is broken. Its not that clear an optimization...