It would be interesting - if they offered a choice of trad chassis or aluminium chassis with modern suspension, how many would sell of each.
Rear discs are not necessary on a light car and are often fitted to modern cars when drums would do the same job. Probably more to do with standardisation and cost management than need. They look good though!
The present set up of leaf springs at the rear spreads the load between the front hanger and rear hanger. Any sort of trailing arm set up will put most of the load (especially when accelerating) through the front pivots, and the upper mount of the springs/dampers, so it will be focussed just in front of the rear axle. Any IRS tied to a chassis which can twist will be a compromise, because wheel deflection will first twist the softer of the spring or the chassis. At least a live axle keeps the rear wheels vertical for most of the time. Perhaps an improved chassis is a way forward without resorting to an aluminium tub.
What would tempt me is a 4 cyl engine with 250bhp in a footprint somewhere between the current 4/4 and Plus4. But not sketched as a competition car which is the usual trend, but as a tourer with a spare wheel. The 4/4 2 Litre is almost my perfect Morgan (with more power). I would want a two plus four instrument dash from the mid 00's and an easy up hood, and over riders. So they almost make my ideal car now.
MMC focus far too much on competition imagery when the evidence seems to be that the majority of aging buyers are more interested in Sunday lunch.