Radiators are 100% developed and also manufactured by us. That is why we are the only company to have genuine all-copper radiators, where all water-bearing parts are made of copper. The only exceptions are the threads, which are made of brass: Copper would be too soft for this. All other manufacturers do not have copper channels but use steel or other materials to conduct the water from pre-chamber to pre-chamber and to transfer the heat to the fins.
Your idea would of course be feasible, but would roughly triple the cost of a radiator. It's not as simple as you imagine. Because the channel lengths would have to be adapted separately for the offset threads, and that is one of the most expensive points in the manufacture of a radiator.
By the way, there is no dead angle for the air. There is always some space between the fan and the cooling fins so that an air bed can form between the fan and the cooling fins. This is further increased with a fan shroud. As a result, air flows relatively evenly through the radiator.
180/200mm radiators also have such a low heat load that these radiator sizes are actually not worth selling at all. The fact that we offer them at all is solely due to the fact that we were the only manufacturer who wanted to offer all possible sizes. We are the only manufacturer that actually covers all fan sizes. 40, 50, 60, 80, 92, 12, 140, 180/200mm radiators in all shapes, thicknesses and sizes. No one else has that.