Tactics: Maiden

Strategies
The Maiden uses all her abilities at random, thus if for example the Repentance cooldown is over this does not mean that she will cast one next, it just means that it's *possible* for her to cast one.

Positioning
Correct positioning of the raid is the key here, healer positioning in particular. Ranged and healers should be far enough away from the Maiden to be outside of the Holy Ground attack. At the same time, the whole raid needs to be in range and sight of a dispeller and be spread out far enough to avoid chaining Holy Wrath. These requirements are easily matched with the following setup:

There are 8 pillars around the room. Put one non-melee raid member at the outside wall in each gap between two pillars. Place the healers next to each other. Melee and tank can start wherever they like.

Tank her in the center of the room, right where she stands. After the pull, the raid members all move to their assigned gap between the pillars, and take exactly one step up the stair leading to her. This puts the whole raid in LoS, healing and dispel range of each other, but far enough apart to prevent the Holy Wrath from hitting more than the melee group.

Instead of standing between the pillars, it's just as good if the raid members stand with their backs to the pillars. Just synchronize so that everybody takes the left (or right) pillar, and not two people end up using the same.

Repentance
Wipes occur at this boss for mainly two reasons - either the tank dies while the healers are incapacitated from a Repentance, or too many raid members die from Holy Fire.

There are several ways to survive Repentance:

Paladins can cast Blessing of Sacrifice (rank 1) on any melee character to constantly take damage, breaking the effect.
A healer (preferably one which cannot dispel) can move into the Holy Ground after the Repentance cooldown is over. Since it can take a while until she casts Repentance, this may effectively take the healer out of the combat for a while (due to the silence effect). This also increases the danger from a chained Holy Wrath. After she's cast Repentance, the healer must immediately move out of Holy Gound and start healing.
The tank can move the Maiden towards a healer, to wake up the healer with damage from Holy Ground. This is easier if one healer stands one step closer to the center of the room, best would be behind the tank. Don't forget to immediately leave Holy Ground because of the silence.
A nice macro for the tank, if they're a warrior, to use during repentance is:

/target [Priest/Healers name]
/cast Intervene
/targetlasttarget
The tank can be loaded with HoT spells.
The tank can use cooldown moves such as Last Stand.
Druids who are otherwise doing melee damage in cat form on the Maiden can run out of the Holy Ground during Repentance and heal the tank.
Easiest way to work Maiden is have a tree druid. Dot heals every time repentance cooldown is up. Renew, and all 3 of the druids heals can last a tank through repentance. Make sure he is always on full life, after repentance have a pally/priest cast highest rank flash/quick heal in order to boost tank back to full life. Tank also has pot, last stand, shield wall and healthstone or 2 so this can also help.
Just ensure that after repentance is clear, REGARDLESS of anyone's health, someone should flash heal the MT. You DO NOT NEED TO heal through repentance. Spec if your tank is geared, and you have enough HoTs (druid and priest are fine).

Holy Fire
The easiest method to deal with Holy Fire is to have Grounding Totems up, with an alert Shaman and a little luck this one totem can absorb all Holy Fires targeted at that group. With one shaman in each group the fight actually becomes quite easy.

If no grounding totems are up, the healers and dispellers must be very alert. Every raid member needs to be topped off at all times, and Holy Fires must be dispelled as quickly as possible. This cannot be stressed enough, as it is the most important aspect of the fight: Dispel as fast as possible. Unless someone would die, cancel the spell you're currently casting to dispel immediately, so you spend less time healing damage dealers back up. Some raids place two dedicated dispellers on opposite ends of the room.

Holy Fire can also be spell reflected, and warlocks can cleanse themselves with Spellstones. Potions which remove magic effects should also work. It actually deals fire damage (not holy), thus fire protection potions are useful, and the damage could be resisted with appropriate gear. Still, it is not advisable to stack high fire resist on every raid member due to the low rate of fire for this ability, and the randomness of the targeting