I know what you mean about Malygos being difficult for Holy Paladins (and even other classes that don't have instant heal or HoT capabilities), but Heroic Loken isn't difficult if you know the fight and use Beacon of Light effectively (which took me the better half of three runs, I'm ashamed to admit), and I'm not sure about which part of Heroic Nexus you're talking about, but Grand Magus Telestra comes to mind, in which case Holy Shock still works while you're being tossed around in the air like a rag doll.

We may have it 'harder' in some regards, but we've still come a long way from the struggling class that was little more than 'cleanse duty' and backup priests in the Molten Core days of old.

What's so hard about Loken? Granted, I only healed it once on heroic but it wasn't any different in a major way from the regular. Tell your group to step out on nova, stack as close to the tank as possible, throw bacon at your tank, reserve shocks for yourself, spam HLs and use infused FoLs while running. Oh and bring decent deeps for the Timely Death achievement.
Unfortunately, can't heal through 5 people hit by his nova, so cannot just ignore it. This might change with 3.0.8 though.

I'm sure your hungry tanks appreciate it when you throw bacon at them.