I'll play Horde. But will be harder to progress through in raids compared to Alliance.
Paladins:
1) Blessing of Kings: 10% to ALL stats for the entire raid. HUGE buff, extra HP for all, Int/Spi Casters, Avoidance for Tanks, More DPS.
2) Blessing of Salvation: 30% less threat, meaning DPS does not have to hold back that much.
3) Blessing of Wisdom: Mana regeneration
4) Blessing of Might: More attack power
- On top of that there are various auras Paladins bring to their group.
- And if that was not enough, a boss could also be judged with Seal of Light or Seal of Wisdom
Fear Ward overrated: Horde has Tremor Totem, Undead with WoTF, Warriors can stance dance. Only some bosses Fear.
Windfury Totem overrated: Only works for melee (Excluding Feral Druids), Rogues can't use poisons.
To sum it up:
4 Paladins can buff the ENTIRE raid with 4 buffs, support 4 groups with an Aura, Judge the boss to benefit the ENTIRE raid.
4 Shamans can buff HALF a raid with 4 buffs having a LIMITED range, no extra aura or debuff on the boss.
My personal opinion:
At the end of the day I think Blessing of Kings is the biggest imbalance between factions. One having 10% more stats than the other.
EDIT: But you can get around that by having two people make an Alliance Priest and Paladin,
Use Mind Control on few key raid members, buff Greater Blessing of Kings.
15 Min buff should be enough for a harder boss pull.
But keep this a secret