I always thought that traffic signals should be trying to minimize squared anger, where anger increases linearly with time spent waiting at intersection.
Also red left turn signals should not be a thing. If there's a gap in the oncoming traffic you should be allowed to turn left across it as long as the straight-ahead traffic has a green light.
Where I live (in the PNW) they mostly are not a thing any more. The only ones remaining are there because the combination of sight line and traffic speed makes them too dangerous to turn into flashing yellow. Not sure if that has spread to other regions, but I would guess it is heading towards being universal pretty quickly.
The only possible second-or-third order effect of red cross-traffic arrows is to decrease the downstream traffic on the cross road. Mostly, the places where I encounter them have a low traffic cross road. IMHO, in those situations, red cross-traffic arrows are simply a failed "traffic engineering fad".
(Edited to fix a typo and generalize "red left-arrow" to "red cross-traffic arrow" to account for left-side-of-the-road driving systems.)