As Tim says, if there is any disappointment, it was about US Tank Destroyer doctrine, largely as they were misused as tanks. Everybody else’s tank destroyers got on with destroying tanks. The doctrine is still in use today, albeit implemented by attack helicopters. Same with battle cruisers, heavy cruisers misused as battleships. When used in their intended role (Armoured cruiser killers) as at The Falklands, they worked very well.
I suppose if you put a rotating turret on a tank destroyer – Hellcat/M10/M36, then it’s going to get used as an ersatz tank. Which I also suppose goes hand in hand with US doctrine of using real tanks for infantry support.
If so, does that mean there is a specific advantage in designing some types of military kit so it can’t be mistaken for a different type of weapon?