The proper gearing is necessary as others have pointed out BUT if you want to have real hybrid capability you need something other than a single speed hub motor unless it is brutally powerful and then your input lessens.
I have a geared hub driven 21 speed trike and the motor is great for hills and lower speed but the moment I exceed 20 kph I am hauling the battery and motor as excess weight.
So for a multi speed motor drive your options are limited the Cyclone system will allow you and the motor to share the rear gearing and is fine for moderately hilly terrain for more gear range for both you and the motor you need to go to a Bottom Bracket drive then even with a low powered asssist you can add combined power from start to 60+ kph.
Mine is low pwered enough to allow me to just go full throttle at startup and then pedal and shift as normal, I just accelerate faster and go faster and can completely ignore the motor to the extent that I am considering throwing the twist grip and replacing it with a switch.