This is great because it will make certain dual craft items able to be HQed more easily, and gives people who didn't want to undo a lot of work the chance to try another craft. On top of this, it can potentially reduce the number of people required to perform more advanced synergy (It could also [ugh] mean that more subcrafts would be possible, though).

Given how stagnant crafting is right now, I don't really see this doing much harm to anyone. It will also give die-hard crafters something to do.