Yea, it's becoming a bit of a catch phrase now :) Well, for ret pallies, they had devie storm which was holy damage. No one has any type of resistant/mitigation against it except for resilience. Changing it to physical dmg wasn't a huge nerf but imo, more of a good change.
Also, the other thing that is a bit iffy is their ability to bubble for 12 seconds and still dish out huge dmg. Now the downside of bubbling is that they attack 100% slower...this is fine, but then Blizzard decided to give them 3 powerful instant cast attacks on small cds which make the speed penalty moot. Not to mention the 2 other spells which got changed to instant cast spells.
Those above are the two problems I find with the ret spec and my reasons for it. Possibly also add in LoH becoming a 5 min spell, if you don't think going from whatever to 100% health instantly, as a dps spec, isn't OP, then there really isn't enough explaining in the world to make you understand.
PS: Now pallies can understand the mana problems which hunters have had to deal with for over a year, which are still worse than pallies.