On your comment about capsizing in typhoons, that was due to Admiral Halsey ordering the fleet to reverse course back into a typhoon AFTER THE FUEL TANKS WERE PUMPED OUT!!!!!!!!!!!!!!!!!!!!!!! The Fletcher class destroyers maintained stability by filling tanks with seawater as they burned off fuel. The tanks were then pumped out to make room before refueling from tankers. When Halsey ordered a course reversal, the destroyer USS Spence (DD512) was prepping for topping off its tanks and was lost due to not being able to reballast with seawater in time to prevent hitting the storm in a topheavy state.
With all of that said, AS DESIGNED, the Fletcher class were actually very stable. As WWII wore on, they did gain a considerable amount of added topside weight due to additional radar antennas and, to a greater extent, more 20 and 40mm antiaircraft guns. This did make the class roll more in high speed turns and rough seas but not to the point of being dangerous as was implied considering no other Fletch class destroyers were lost due to rough seas alone. Of the class, one was lost due to the typhoon, one was run aground and subsequently destroyed by Japanese shore batteries, one was lost due to mine damage and subsequently beached, one was sunk in the Solomons and two more were sunk at Leyte Gulf in surface actions, two were lost to bombing, one scuttled after serious damage in another surface action while a second was scuttled after a kamikaze strike. Of the rest of the class, 10 were sunk by Kamikaze planes while six more were damaged to the point of being beyond repair and one other repaired but it failed it's post repair sea trials. All told, there were 175 Fletchers built and 19 lost both during and after the war. After WWII, a few were damaged beyond repair due to collisions with other vessels. As a general note, I served with the airwing on the USS Kitty Hawk (CV63) for two deployments and have gone on a couple of pleasure cruises since and every time the vessel has turned, they have heeled over toward the outside of the turn in anything other than a slow turn so this is not something specific to the Fletcher class