Flight envelope
The TR Thrust does play a big part. For example in a heli whose blades rotate counter-clockwise the torque reaction provides a rotation clockwise which the tail rotor must be able to thrust against. In a R22 for example this gives a sideways thrust to the right. Tail rotor drift some people call it. As you pick the heli up into the hover in order to prevent immediate sideways flight the cyclic must be positioned to the left. This can often reflect the reason why the heli may hover left skid low. You therefore have less available cyclic input to the left which would affect the flight envelope.
But that's my take on it. Somebody else may have a better explanation. Maybe Igor.