The idea that less / fewer road signs and markings make for better road safety is not new, and indeed has been part of the design of roads and junctions for some time.
The idea is to make drivers more situationally aware of their relationship to other drivers and hazards, not to make the driving more hazardous.
So, fewer instructions on rights of way, imperatives and priorities, and less information signs beyond the immediate situation, mean the driver must work out what is safe and appropriate in the immediate situation. ie each must check decisions with the behaviour other road users rather than take your own rights of way for granted as signposted.
Signs and layouts that help you see and better judge the road and other users are essential. Driving lights, hi-vis panels, cats-eyes, curves that increase lines of sight, clearance of visual obstructions, white carriageway lines (without instructions) all help visualise your situation.
Making roads more hazardous – making it harder for a driver to judge available safe space – will tend to slow down cautious drivers, but unless your objective was to increase travel times, the slower speed won’t reduce the hazard. It’s the increased hazard that is reducing the speed. How dumb is that?