The Jewelcrafting nerf has been the subject of a lot of hot debate and flaming on the official forums, as might be expected. As people argue whether the nerf was justified, needed, too much, too little, or the wrong way to go about it, the blues have dipped their toes into the pool more than once, and have delivered some interesting insights into the design process in the process.
If it was so overpowered, complain some, why did it take so long to nerf it? Ghostcrawler answers in this post.
It's not that they don't notice that something is overpowered, he says, but it does take some time to find a proper fix. Sometimes, it just isn't overpowered until a certain gear level. Sometimes, there may be bug fixes or larger problems that need answering first.Sometimes, they may need to debate over the proper way to fix it. Finally, they may have a more ambitious long-term solution in mind, and may have finally decided they can't delay until that's done.