There's an intermediate segment still dominated by the Beechcraft 1900, the Metroliner or the Embraer Brasilia.
German pundits say that when it first flew in the early 1990s, the Do 328 was far too advanced and over-engineered to become a bestseller at the time.
But they think the aircraft might fare better nowadays. The "old" 328 offers a great deal of comfort, reflected by an above-average amount used as corporate aircraft or air ambulances; and should the manufacturer be able to keep its promises of increasing the new 328's range and speed, the new installment should not only be able to attract current operators of the Do 328 but also raise interest from airlines operating those other types, many of which are not in production anymore and need a replacement.
Besides, the American parent company of 328SS seems to think they'll be able to sell the new aircraft to the USAF, which already operates a sizable fleet of second-hand 328's. Last but not least, they want to be the first to produce an electrically propelled regional aircraft. They've acquired the assistance of the German Aerospace Center (DLR) for this undertaking.
On the other hand, this joint venture might come too late to succeed, and Dornier projects have had a history of being too expensive to be competitive. Just a couple of weeks ago, Switzerland's RUAG announced to end production of the Dornier 228NG, a reiteration of that classic turboprop. No one denies the series' ruggedness and exceptional utility, of which many serve in militaries or under harsh conditions (such as airliners in the Himalaya) – but although a lot of them are ageing and need urgent replacing, RUAG could only sell like a dozen NGs.
