Alright, so this isn't at the top of anyone's list of bugs to fix, but my blog is called "What's Wrong with WoW" and this is something that's wrong with WoW. It's also rather amusing.
What happens when a Death Knight gets Lucifron's Curse? In part, exactly what you'd expect. Your ability cost double runes or runic power. And then a few things you wouldn't expect. For one, you don't generate runic power anymore. I've tried to think out the logic on this and my best guess is that when it tries to give you runic power it notices it's giving you 20 and then things that that means the ability costs 20 so it makes it cost 20 more, subtracting 20 from the 20 you were supposed to get and giving you zero. Just speculation, but it makes some sense.
More sense than the next bit anyway: If all your non-blood runes are death runes, and you use an ability that uses both your blood runes, your death runes immediately refresh. Then, after you use them the first time, instead of refilling two at a time as they should, all four refill at the same time. The result is that you get to alternate two death strikes per Heart Strike. This behaviour is just plan bizarre, and doesn't seem to have any reason behind it.
On to paladins. What happens when you use an ability that costs holy power? Well, it uses two of your three holy power, presumably because with costs doubled it can't use three. It tries to use one, uses two, then can't use another one. But the ability you use hits as though three holy power were used. Apparently when you use a holy power ability, it checks how much holy power you have first to see how powerful the ability should be, then it spends the holy power - apparently one at a time. How much you spend doesn't matter, how much you had matters.
I should really bring a balance druid down to Lucifron and see if something crazy happens with eclipse.