Well, seeing as we've already drifted the thread, two things:
Yes, helicopters have an "avoid zone" of airspeed vs altitude for a safe gliding return for a landing. Fixed wing planes have an avoid zone too, it's just not published, and not taught. For helicopter pilots it's prime information during training, and in flight manuals. Ask yourself, like a helicopter, if you were flying your Cessna at 100 AGL, and 50 MPH could you enter a glide after a sudden engine failure, and accelerate to glide speed so as to be able to flare for a safe landing - before you hit the ground? No, a fixed wing plane won't do it either, just no one tells you, 'cause you're probably no supposed to be flying there. Sometimes helicopters have to, so it's published and trained.
And, yes, helicopters produce wake turbulence. It does change shape from the hover to cruise flight, though it's going to have the same negative effects on airplanes who might blunder into it, as would be the case of the airplane flying into the wake of another airplane.
Helicopter pilots may be given more direct traffic patterns, but be confident that ATC, and the helicopter pilot themselves are well aware of the burden of traffic avoidance (and the helicopter pilot has the better view!).
Helicopters have surprising similarities to airplanes in ways you would not expect.