Be careful not to confuse the comparison of a WWII technology engine with a 21st century engine, but really an Otto vs. Diesel comparison !
In principal if you need a light engine which is most efficient close to maximum power and does have its maximum torque close to max power (this is what an aircraft and a propeller requires) then Otto is the clear answer.
If you want to have the best absolute efficiency and the highest efficiency at low power levels, including high torque at low speed (this is, what cars and even more trucks require) then Diesel is the answer.
Limiting factor for Otto is the speed of the flame which limits the size of the zylinder. This means you can not efficiently produce more than approximately 50 hp per zylinder (uncharged) at a typical propeller speed. So it is either a geared engine or lots of zylinders or supercharging if you want to go beyond 300 hp. For Diesel it is more the speed, than the zylinder size which limits it, which is no problem as propellers need to run 1500-2500 U/min depending on the exact diameter epending on the total power you need. This is about the speed at which an ungeared Diesel is best.
As aircraft engines are all about flying, meaning high altitude, turbocharging is almost a must if you do not want to have "high and hot" density issues. Diesel are much easier and much more efficient to turbocharge.
hope that helps