For all the praise lavished on the DHC-2 Beaver, I don't think anyone has ever called it ergonomic. They were designed back when you were supposed to be a real man in order to fly an a airplane and if you couldn't cope with the fact that the levers weren't in the standard order on the throttle quadrant (as they were on one I flew) then you weren't man enough. I can't remember if it was the throttle and prop, prop and mixture or mixture and throttle that were switched, and the fact that I don't remember perhaps illustrates the problem. Imagine if one of the cars you drove had the accelerator and brake pedal switched. Or maybe the accelerator and clutch. It wasn't the designer's fault in those days.
One of the problems with Beavers has been the door handle. It was designed to close securely, and probably was cool and modern, or at least normal in 1947, but twenty-first century passengers have grown accustomed to a different style and standard of exit door from a vehicle, and have not found it to be an intuitive escape route. Deaths in otherwise survivable accidents have led to a redesign of the door handle, something that is a little unusual in an out of production aircraft, but they are still so popular that a different manufacturer has the licence to make parts for them and has taken on the responsibility of the replacement door handle.
Also: The TSB recommended floatplane passengers wear lifejackets but the airlines object. They say it's because passengers might inflate the jackets inside the airplane, hampering their escape. That's a true risk, and has caused fatalities in water landings, but I personally think there is at least as much, if not more, risk of a passenger inflating a lifejacket inside an aircraft if they have just put it on than if they are already wearing it. And there is certainly more risk of not having a lifejacket on when you need it if you have to put it on in the time period between realizing there is a problem and escaping the aircraft. I was once present when a large floatplane dug a wingtip into the water during landing, and the only person who got the lifejacket out from under his seat during the crucial seconds before the airplane fortunately didn't require an emergency evacuation, was a jumpseating captain. The real reasons the airlines don't want to put lifejackets on passengers before every departure are time, cost and did you see Six Days Seven Nights? Notice that despite all the commercial seaplane flights depicted being in the same type with the same pilot, the only flight in which the pilot required the passengers to wear lifejackets was the one in which the premise required them to be nervous and seem ridiculous.