212man,
You are right there, but be careful, because the Fantail was considerably more robust than a fenestron on a Gazelle! I would bet the EC folks might really complain if people kicked around a fenestron helo as if it were Comanche!
The high speed handling of the Gazelle I once compared to a good airplane, it was so nice. Those endplates make it really uncoupled and docile. You are aslo quite right about the effects of an anti-torque system failure. Because virtually all antitorque at high speed in a fenestron comes from the fin and endplates, loss of the fan at cruise is a much more managable affair.