Threewheeler of HD? Leaning over in curves? No way, no trike, no three wheeler for me. When I become too old and weak to keep my bike upright for a traffic light I will mount a sidecar. At least I keep the feeling of riding a motorbike.
A sidecar by no means feels like riding a motorcycle. Don't get me wrong, I will do the same thing. I have a sidecar and love them, if I need three wheels, it will be a sidecar. But, it's a totally different experience.
Where I am I have noticed the Can Am Spyders seem to be growing in popularity. I agree the two wheels up front and ability to lean would be much better than a Tri-Glide with the two car tires on the back. Odd that HD didn't market these, I bet at some point they will.