Like I said Frank, (and it looks like you've agreed with, but in your own words) Choppers are great in a straight line, but useless on anything but nice straight, smooth roads. Most have extended forks, many have no rear suspension, just about all have very low ground clearance, and many don't even run front brakes. Sure, you can put really good brakes on one, but how many people do? I watch lots of chopper shows on cable, and most of the builders don't even fit a front brake at all.
If they really were "Performance bikes", people would race them. I go to a lot of classic race meetings where many, many Honda CB750's are still raced, but so far, I haven't ever seen one chopper in the pits? I do see plenty in the car parks though, which is probably the safest place for them, with lots of sparkly chrome and big dollar paint jobs, the last thing you'd want to do is lay one down.
Choppers are motorcycle art, extreme form over function, and I love them, but they will never be considered "Performance" bikes by anyone with half a brain. Cheers, Terry.