Most of the FW-190s seen at airshows are really Hispano HA-1112 "buchon" aircrafts, which were built in Spain with license from Messerschmitt AG during WWII and after. They remained in service until the sixties in the spanish Air Force.
I would definitively ground the last real WWII warbirds remaining in the world and keep them in museums for future generations to admire. It is horrible everytime one crashes, both because the loss of life and for the destruction of a museum piece.
I've attended several air shows over the years and it's great to walk up and see and touch them,take pics etc. And to see em fly! But I can see your point about grounding them for posterity. (in a way)Me..I want to see them fly!