I for one, wouldn't want metal roof vent covers. These are attached to the coach roof - which is fiberglass in my case - and if it were hit by a low branch would likely take part of the roof with it. While the roof is fiberglass, it does not really have any structural strength unlike fiberglass used on boats.
While I generally agree that metal in appliances is preferable to plastic, I would think that it would add extra weight and cost. Appliances are really commodities today and I think most consumers would not attribute incremental value to metal if other brands used plastic and would likely buy the cheaper product. Newer appliances are largely disposable and not like older ones that could be economically repaired. My 2 cents worth!
09 Journey 39Z