I'm one of those people who haven't gotten a key. I haven't seen the actual Abyss yet.
My solution, though, is to make him a lot harder, like at least Baracoon-level or more. More people will get looting rights; it'll be a lot more fun; and he'll finally match his artifact in power.
The ease of killing him has the strong feel of a bug. If so it should be top priority to fix.
And if it was intended this way, they need to slap themselves for making a stupid decision, and then change it. (And it should be top priority.)
Can't get much more crucial than access to the main reason content of the expansion!
-Galen's player