Light cars can ride well, it's just that the A2 (and particularly the factory Sport chassis) is typically old-school Audi, i.e. too stiffly sprung and too firmly damped. Whoever signed off the Sport chassis with the 17" wheels had clearly never driven it around a UK city ...
It is all a matter of personal taste. I am happy to sacrifice a little softness to get improved handling, especially when cornering. But I agree that if you want a soft ride then the sport on 17" is not ideal.
As for soft cars riding well, I also agree, but that is at the expense of stability. Softer suspension can be too soft, especially when cornering. And even in straight line speed, wind can affect the car more of softer suspension (remember the old A class Mercedes problems where they would roll over when driven fast on a slalom type course (mainly due to the car being light on soft suspension).
The A2 smart for two cars also suffer straight line stability at speed when it is windy. They have a reasonably smooth ride due to the soft suspension, but the stability suffers for it.
I guess the best compromise is softer springing with stronger Anti Roll bars. That way you get increased firmness when cornering without any increase in straight line stiffness.
But the bottom line is that you either want a soft ride for comfort or a firm ride for cornering.
I think that you can get close to both in an A2, depending on how you set up the shocks, springs and ARBs. To me the Sport suspension on 18" wheels gives me exactly the ride I want (and it is not a bone shaker in any way, even with that set up)
In my opinion of course.
Steve B