Let's take a look at the upcoming level 100 Holy Paladin talents in Warlords of Draenor.
The first thing to note is that Blizzard is effectively making different talents for each spec. The three Holy talents are completely different than the Retribution and Protection talents. Retribution and Protection do share two talents, but have a different third talent.
Beacon of Faith - Mark a second target as a Beacon, mimicking the effects of Beacon of Light.
Pretty straightforward, but also very easy to use and understand. Great in raids where you can simply beacon both tanks. In 5-mans, it's probably weaker, but you can always beacon yourself and not have to worry about your own health.
Note that if AoE healing becomes significantly weaker, this might prove to be quite powerful, as you are now healing three people at the same time with your single-target spells.
Beacon of Insight - Places a beacon of insight on an ally, increasing their healing received from your next direct single-target heal within 1 min by 30%. When consumed, or when the target reaches full health, it moves to the most injured ally within 40 yards. Limit 1.
One of your injured allies will always have a buff giving a boost to your heal. However, it is a little unpredictable in practice, as it will bounce around the group. But as it always bounces to the the most-injured ally, that probably is the one you should heal.
Heh, in some respects, this reminds me of that old Vanilla mod which would arrange players by health, and the healer would just heal the top bar. You could probably do a semi-decent job just by chasing the beacon around.
One open question is how Blizzard defines "most injured". Is it most injured as percent of health, as absolute amount of health remaining, or absolute amount of health lost? Each of those scenarios results in slightly different patterns in the bouncing. For example, absolute amount of health lost means the beacon will usually jump to a tank. Absolute amount of health remaining means it will probably bounce around the dps.
Saved by the Light - When you or your Beacon of Light target drop below 30% health, you instantly grant the injured target a protective shield, absorbing up to 30% of their maximum health for 10 sec. You cannot shield the same person this way twice within 1 min.
I will assume that this means that if you drop below 30%, you get a shield. If the beacon target drops below 30%, she gets a shield.
This is excellent for single tank fights, giving your tank another emergency cooldown. I don't think the personal shield will see much use in PvE, but it's always helpful to have. I can see this being the talent of choice in PvP, though.
The thing about this talent is that if things go well, it will never be used. But it might also be the factor which prevents a wipe and results in a successful kill. It's very strong against unexpected spikes.
On the other hand, the other two talents will straight up increase your throughput. That increased throughput might prevent the tank from ever getting that low in the first place.
I think all three talents are pretty interesting. I would probably use Beacon of Faith for raids, and one of the other two for 5-mans. But I can see it depending a lot on the fight and what your assignment is.