Suppose you have to hover next to a cliff or hangar with some serious crosswind. Consider the following:
Is a fixed pitch variable speed electric motor dynamic enough to hold the tail steady? What about tail rotor rpm wind down when the gusts abate, do you need tail rotor brakes?
Perhaps variable pitch constant speed is the better electric option of the two. Now how do you manage power available on two different systems. Will the electric motor run out of puff while the coal burners are just warming up? Are bigger electric motors needed along with all the penalties that introduces?
Some of us like to roll the helicopter in tiny amounts just using the pedals, will the electric fan at the back take this away from us?
Now if you are gunna stick an electric fan at the back at least allow it to pivot around 90 degrees to provide forward thrust.