replace the chassis/ suspension on the Trads with something more up to date you could just end up with a car that looks like a classic but rides and handles like a modern car and where is the fun in that? - neither the 4/4 or +4 have enough power to tax a modern set up, the result- no sports car but a genteel jalopy for bimbling around the Cotswolds
I don't think anyone would propose fitting American Limousine suspension to a Morgan. Apart from any other consideration the space would not allow it. Also I am not even saying that there is a particular problem with sliding axle suspension in terms of ride and handling but it is clear that the maintenance costs, in terms of both time and money, and the need to replace the king pins at relatively low mileage are a drawback.
I don't think anyone would accuse a Lotus or a Ferrari of have a jalopy ride. It is not so much a matter of power but how fast you throw the car into a corner and the cornering dynamics that matter. In terms of power to weight etc. the latest Roadster must surely be pushing the limits of the current configuration.
Regarding the rear suspension of the Morgan there would have to be several alternatives to give independent rear suspension in the space available without detracting from the Morgan experience. No doubt the current setup is less expensive to make.
Whatever the case a live axle rear suspension system has the disadvantage of heavier unsprung weight and shocks are also transmitted directly to the other side of the car. All in all this makes it more difficult to keep the rubber in contact with the road and leads to a harsher ride for the occupants.
Personally I have never bimbled anywhere as a long list of speeding fines will attest