So you can get Keening in Skyrim from a quest.

...Keening? Without Wraithguard? I mean with the heart of Lorkhan destroyed...I guess THAT would excuse the fact that holding Keening without Wraithguard doesn't 1-shot you.

What are your thoughts on this?

The Heart of Lorkhan wasn't destroyed.

Possibly the fact that you're dragonborn means Keening can't kill you. Or maybe it's a scripting error.

Well I won't give the quest away but suffice to say your not the only one to hold Keening, another person wields it before you get it, and before that a courier handles it unwrapped. And the Heart wasn't destroyed but you certainly took away its power. Which is why I think anyone can hold Keening since after the Morrowind MQ I'm guessing eventually Keening, Sunder and even Wraithguard would lose their powers

You didn't take away the hearts power either. You just took away enchantments on the heart, freeing it again. But Keening and Sunder were never anything more then tools to create and manipulate those enchantments. There is no reason I can think of why they would become weaker without the Hearts enchantments active. We are talking about Dwemer items after all.

You just don't get to see the real item in Skyrim...

Regardless I would love to see an explanation as you why a random mage, a courier and the Dragonborn can hold Keening in their hand and not be killed, when in Morrowind all you heard about was "Without Wraithguard Keening and Sunder will kill any who touch them"

Maybe it's not really Keening.

That is, what Fishy87 said.

"Kagrenac's Tools are cursed. Stealing power from the heart of a god is a terrible folly, and fated to disaster" - Gilvas Barelo, Kagrenac's Tools

When the heart was freed, maybe the curse on the tools was also lifted?

Why? The tools needed wraithguard the first time they were used, I see no reason to believe that the destruction of the enchantments somehow made Keening less powerful. I'm still going with you had a fake Keening.