Hi I've been riding and fixing/building bikes since the70 s thought I would chime in
In a nutshell bigger riders need bigger bikes.Harleys get a bad rap as not good beginner bikes.I disagree There are weight limits for smaller bikes.Overloading any bike bike is dangerous.Any one close to 200 # should be considering at least a 750.People will not respect a bike without abundant power.The tourqe of a Harley in comparison to higher rpm Horsepower of an inline 4 import is more conducive to learning.The inline for will make usable power at bottom and mid range rpm.As the rider gets more confident they will discover a massive amount of power remains in the upper rpms.That rider then has to re learn how to handle that or accept he is only using 15 % of the power his bike makes.Then he either gets reckless or bored with the bike.
On the other hand the Harley or any v twin learner experiences all the tourqe on day 1The linear power band is more predictable
Harley and Cruiser rider seat heights and minimal ground clearance keep center of gravity low and manageable on the road and in parking lots with knees comfortably bent
For handling minimal rake angle and a matched set of tires and a low center rof gravity is good.Softtails are the worst stock handler because of excessive rake angle and uneven tire widths front to rear.They look cool as hell though.
A good handling bike is more important for a new rider
Safe riding is more about Defensive attitude maintaining focus visibility And understanding ALL the physics involved.A new rider shouldn't have to worry about outgrowing his bike.Riding is a lifetime of learning Physics and studying local condition meeting people and enjoying the ride