Theoretically they could give a better spark especially at high rpm. The reason is that the coil has nearly two full rotations of the crankshaft to recharge between firings. The problem that I see is if you really went coil-on-plug in nearly any kind of a wedge engine you risk cooking the coils with exhaust heat. So you'd go with the coil and short plug wire or possibly a rigid insulated conductor.

The Electromotive ignition setup used this principle.

R.