Freya starts off with 150 stacks of her "Attuned to Nature" buff, making it impossible to out DPS her constant self-healing ability. Killing all the adds that periodically spawn throughout the fight remove stacks of this buff.
-Ancient Protector (a large add with over 1mil HP in 10 man. The raid must be stacked under the mushrooms that spawn in order to avoid his silence aura.) He also throws out a debuff which works similar to that of phase1 of Lady Vashj, if you have it, move away from raid members.
- Detonating Lashers (a bunch of small adds, they do not have a lot of HP and are untankable. When they die they explode for a solid amount of damage, so be careful when dealing with these).
- Snaplasher, Storm Lasher and Ancient Water Elemental (Three adds who must be killed within ~12 seconds of each other, or they will come back to life. The Snaplasher becomes stronger and slower over time, the Storm Lasher does AoE lightning abilities, and the ancient water elemental does a frontal AoE attack). Note: On 25 man, I strongly reccomend having your tank kite snaplasher when he begins reaching ~40 stacks of his debuff (assuming elder ironbranch is dead).
Healing this watcher is not hard at all, just keep sure you notice everything of your surrondings, get under a mushroom when a big raid warning comes, and everything will be alright. For Paladins, Beacon of light on your MT, and have a flash of light feast on the OT untill there are some adds kicking your OT's butt, give him a holy shock and a couple of flash of lights, then go back to flah of light healing, this fight has some AOE damage to the raid, however, its not that big, if you have a druid or a priest healer with you, they can take care of it while you are having fun (not really) spamming flash of light.
note that the fight is super easy on 10 man, but its a little bit harder on 25, or so i heard.
RECAP: 1.) Keep the MT and the OT topped off (beacon of light is very helpful for both of them) 2.) Run under the big mushrooms when the big warning appears on your screen 3.) Spread out. 4.) Rinse and repeat.