All of the paladin specializations will make use of a new resource called Holy Power. Holy Power accumulates from using Crusader Strike, Holy Shock, and some other talents. Holy Power can be consumed to augment a variety of abilities, including:
An instant mana-free heal: Word of Glory
A buff to increase holy damage done: Inquisition
A massive physical melee attack for Retribution paladins: Templar’s Verdict
Holy Shield’s duration is now extended by Holy Power
Divine Storm’s damage is now increased by Holy Power
Templar’s Verdict: An instant weapon attack that causes a percentage of weapon damage. Consumes all applications of Holy Power to increase damage dealt:
1 Holy Power: 55% Weapon Damage
2 Holy Power: 125% Weapon Damage
3 Holy Power: 225% Weapon Damage
Word of Glory: Consumes all Holy Power to heal a friendly target for a specific amount per application of Holy Power (0 mana cost, 0 cooldown, instant cast).
It looks like the closest mechanic to this is rogue combo points. Certain of our abilities generate Holy Power, and other abilities will consume all of it, and have an effect proportional to the number of points consumed.
However, where the rogue is focused on combo points, and most GCDs are used either generating or consuming combo points, Holy Power looks to be layered over top of our regular abilities. Paladins look to generate a point of Holy Power every 4-6 seconds using our normal rotation, and use a Holy Power finisher roughly every 12-18 seconds.
I guess that this is intended to make paladin gameplay a little more dynamic, and we weave in Holy Power finishers every so often, or maybe even save them for times when we need burst.
On paper, this seems pretty good. We'll have to see how this plays out. There is always the possibility that tactics getting a 3-stack of Holy Power, then running to a new PVP target and unloading a full-power Templar's Verdict will be deemed overpowered. (And naturally, hotfixed 24 hours after Cataclysm's release.)
The other thing I like are the new paladin ability names. Word of Glory, Inquistion, Templar's Verdict, and Light of Dawn (new cone healing spell mentioned in the Dev chat) are very nice paladin names that avoid resorting to the words Holy, Judgment, Light, Righteousness, and Divine.
On the other hand, "Holy Power" is a rather bland name, and could stand to be spiced up. I suggest using a name that paladins have been waiting to see in WoW since Diablo 2: Zeal.