Bacon, how do I love thee? Let me count the ways.
There's a few approaches you can use to using Beacon of Light in PVE encounters, and your favored approach will likely affect your gut instinct for stat priorities. (This is a mastery post, believe it or not).
The method I've used for most of T11 is to assign myself a tank (ah, the joys of being heal lead, I'm known for giving myself the heaviest tank-healing duty), and Beacon my assignment.
Beaconing Your Tank
For fights like Magmaw, Atramedes, the second half of Halfus, Double Dragons, and Chogall, you've probably already done this. With Beacon on your main assignment, you're free to spam the raid with heals. In 4.2, we can use Holy Light as often as it can cover tank damage (which on one-tank fights can happen, if you've got other paladins using their Beacon the same way and full-rolling hots and shields from other healers).
I like giving my tank my Bacon. It ensures my tank will always be getting a heal (not just the 1/2 direct heal, but tiny heals from PotI and JotP as long as I'm staying active, but on the occassion I do need to land a big heal on the tank, I get Holy Power, which allows me to do even more raid healing with LoD, which transfers a good-sized heal to my tank. More raid healing and solid tank healing. It's win.
This setup favors haste>spirit/crit and employs all spells, potentially favoring Divine Light and Light of Dawn. A paladin has less reason to use Word of Glory unless she's really trying to be mana efficient (crossing her fingers for a HP refund with each WoG use). Casting Divine Light on your tank procs more HP and allows you to spray lots and lots of LoD over the raid, to the point of planning out holy power for big attacks and timers, and regenerating it quickly by spamming the tank with Infusion procs.
This setup makes mastery look like a chump stat. With the changes in 4.2, mastery is better (our bubbles are a little more likely to last long enough over the raid to be absorbed), however, the scatter shot raid-healing approach means a lot of those bubbles can get wasted (phase changes or timed AoE pulses longer than 15 seconds). This approach means we're healing reactively, while mastery really shines with proactive healing.
That's a drawback if you're trying to avoid mastery. We "pay" for it in terms of class balance so for fights we're not able to utilize our bubbles, we're running without one of the tools in our already limited toolkit.
This strategy is solid for fights with moderate tank damage and moderate raid damage, and allows you to switch between direct heal-bombing your tank and raid healing on the fly.
Beaconing Someone Else's Tank
I think a lot of paladins still use this approach (the other two healadins do this unless we agree otherwise). For fights that feature two tanks and limited raid damage, this is a solid way to keep up two targets.
The drawback is, you put your tank in danger when you help heal the raid, because while you aren't healing them, they aren't getting any of your heals. With this setup, WoG shines a teensy bit more than LoD, if a healadin wants to keep constant heals on her tank. (And fights that encourage this type of Bacon may not have raid damage to heal).
Mastery is an amazing stat for this playstyle. I am not yet comfortable with the stat weights for this setup but I have heard other paladins gear for a 1.9 second HL/DL (mine is 2.0 with 790 haste) and enough critical strike rating to keep up solid uptime on Conviction (at 15% crit I kept up 97%). What a healadin gives up in raid-healing flexibility she becomes a beast tank-healer. Constant bubbles on cheap heals. It's ridiculous.
Holy Light takes precedence over Divine Light, since this style is proactive healing, building up bubbles whether the tank needs a heal or not. That means you can get away with less spirit. That means--you guessed it--room for more mastery. Truly a specialist build.
This strategy is awesome for fights with insane tank damage. Your healing team will love you for your mastery and your ability to keep a constant stream of heals and bubbles on the main tank. However, you may feel like the last kid chosen to play at recess for AoE damage fights. For progression-minded raiding groups (and aggressive raid healers who don't care), that may not be a drawback.
I've had two holy specs for a while now. My off-spec was last tuned for Alakir (Pursuit of Justice, go go!) but I've been contemplating redoing that build to fully utilize a mastery playstyle. I think Tower of Radiance is wasted on a full-on mastery build. That's not to say I would scoff at a paladin who had it, but for players like me who prefer to keep two variants of their main spec instead of a true offspec, I think there's room to play around.
I'm writing this post a bit ahead of its post date so I'm going to go with this build here (31/5/5), and hopefully I'll let you know how I feel about it. I'm not really happy about 1/2 Blessed Life but it was the best I could do without taking the DPS talents in the Holy tree.
I'm further thinking that if I'm going this route of having one specialized tank-healing build and a raid-healing build, I could take out Eternal Glory in my raid-healing build and try Pursuit of Justice instead. In theory, I'd be casting far more LoDs than WoGs, and the extra movement to help position myself for Holy Radiance would be helpful. But I'll keep you posted. I haven't decided yet. :)