There is, I gather, a school of thought that says for the money they spent building Tornado from new, they could have restored more than one old loco. And if you're going to built a new steam loco, why not build one up to date, instead of copying an old plan....
I'm not sure where I stand - I guess a lot of people enjoyed doing it, and I'd be happy enough to see a replica Viking longship - although projects like that are often as much to do with understanding the building process as the finished item - I'd assume the process of building a steam loco was fairly well documented....