There have been leaked images and information flowing about the Grey Knigjt codex over the last day. Many if these leaks don't look good for Grey Knights, such as the changes to psycannons to salvo weapons.
At this moment though it's still early to call the codex rushed or shortchanged, although only getting a single week of releases and attention seem a little short.
The best bit of information as well as seeing the leaked images is simply to follow the link here to Blood of Kittens who did an excellent round up of the information without having to deal with all the drama of Dakka or Warseer.
Here is the link.