While that idea makes sense, it could create the problem of changing the light for someone who wants to turn right, which (in the US in many places) is a legal turn to make on red. In the case of small roads merging with larger roads with more traffic it might have the effect of stopping the larger flow of traffic to make little difference for the right on redder...
I hope this comment makes sense. If I could animate some gifs I would do something worthwhile.
