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.