I never said slow coolant down, my point was raising flow when everything else is constant does not have the effect your stating. The industry concentrates on capacity of the system, air flow. Clear Chrysler thought they had the WP size correctly for non ac cars, and when they add the heat load of AC they increase capacity and air flow. The increase air flow also increased water flow, and they then reduced that water flow with a smaller impeller surface area. Why if increased flow is beneficial.

Most studies are on tubes and flat surfaces, not winding path with obstructions inside the water jacket of a block. You don't know the pressure gradients inside the block. One study that was working on electric pumps and valves determined that to have an effect you would need to cool the block from the side with individual control valves for each cylinder.

Yes I misspoke about nb. It is the departure from it when heat flux falls off. Flow alone does not determine dnb other than on a flat plate or tube. But just because NB is maximum heat flux does not mean you want to operate there if you have the cooling capacity. Your at the limit and if you depart your in trouble in those areas localized or not.

Increase flow is increased parasitic loss of power, cavitation and aeration. The last two are not beneficial to flow and heat transfer.