Em, ali will corrode, less so if anodised so stainless would be better....at a significant cost.
Quality is best designed in from the start. It may be cheaper to deal with this pillar blistering under warranty or when out of warranty adopt the " it's a Morgan, we build it and owners develope it! " What effect this has on image of Morgan is another factor too.
I do wonder how MMC watch what happens to cars and the issues they get. There appears to be some level of that going on as cars do mileages to show up problems. Whether a small number of occurences is deemed worthy of resolving is another matter.
Comparing my 1993 4/4 versus the 2002 Plus8 showed clear improvements in quality for trad evolution. The CX is way ahead but, like any make of car, will undergo further development.