Early inline engines had a flywheel to balance out the power strokes. The rotary engine had a better power to weight ratio since the case and cylinders did double duty as a flywheel.
Some of the early rotary engines were controlled by turning the ignition on and off. This led to fouled spark plugs. Later ones had primitive throttle and mixture controls and it was better to shut the fuel off and keep the plugs firing on approach to landing. The ones I've heard at air shows power right up when started, nothing like JT3C response.