The Razorbacks and Sanguinary Priests are something to be concerned about as Marines can now close on Tau positions quickly and unharmed, only to disgorge Space Marines that are very difficult to kill. The codex makes fielding massed S5, AP5 weaponry an exercise in futility. Long range fire is also nerfed as it becomes more difficult to keep your distance when all transports are moving 18 inches a turn and Space Marines are dropping from the skies with the Decent of Angels special rule.
Such times call for improved firepower and the Fio'la of Tau are quickly arming stocks of Battlesuits with crucial Plasma Rifles, Fusion Blasters and Missile Pod in order to deal with such threats. It is becoming increasing important for Tau players to have devastating short range firepower at hand. I am talking about working more plasma and fusion into your list. So that means more Fire Knife Suits or Helios Suits (Fusion Blasters and Plasma Rifles) at this juncture. A good strong unit of Broadsides, maybe with a target lock on their teamleader, is also needed to knock out transports so your Crisis Suits can to focus on wiping out exposed Marines with their plasma and fusion weaponry.
When a unit of Assault troops leaps from a Rhino, you need to be there with high-tech alien weaponry to fry them. When Angels clad in red or black decent on you from the skies, your Crisis Suits should be there, posed to strike the killing blow, completely an utterly. I have been working more plasma into my list and my Deathrains are left in the Battledome for training. A good healthy supply of AP2 weaponry is what you need. Any thing less and your positions will be overrun!
What are you doing to combat this new threat? How have the Blood Angels changed your game?