Right. My idea(based on that article) right now puts them on the level of Terrestials/Sidereals, but only in the Underworld, and in comparison to other ghosts. Yes, they're more powerful than pretty much any given ghost, but as they learned in the Usurption, quantity has a quality all it's own.

This is also why an Abyssal can tell them to STFU without being insta-gibbed; currently, they're about equivalent in power. The only problem is that Deathlords are at the Zenith of their power, while Abyssals still have a lot of room to grow. Heck, none of them have even broken Essence 6 yet.

Also fits with the idea that the Deathlords are training their replacements, though they don't realize it.