I'm convinced I've found something significant on Revelations that's worth checking out.
Alright, This is what happened:
My friend and I spawned and we immediately shot the character's tombstones in the correct order. After receiving the visual (fire) and auditory (thunder) indicators, I proceeded to take the wisp on the truck's headlight and the bottom right section of my HUD started sparking (which always happens after picking up the wisp). (***My friend has not yet completed the previous EEs and couldn't pick up the wisp***). After taking the wisp, we powered up the Corruption Generator in the spawn area. After completing the ritual, the sparks indicating I had the wisp disappeared and a blue bolt of electricity began to strike the tops of the 4 floating rocks. This blue bolt of electricity accompanied the usual red bolts that hit after completing the ritual. After that, I was no longer able to pick up the wisp, which led me to believe this has to be done with 4 players in order to carry out the same procedure for the other generators.
I can pretty much confirm that this wasn't a texture glitch, as I was able to duplicate it numerous times.
I can also confirm that if you take any damage while possessing the wisp, you will lose the spark indicator and subsequently will not be able to complete this "step".
Make of this what you will, I just thought it would be an interesting piece of information for the EE hunters out there. I highly suggest you try this out for yourself, as that will confirm or debunk this theory. Let me know what you find. If this turns out to be the first step to the EE, I'll be delightfully surprised. If it doesn't, at least we tried.
UPDATE: Glitching Queen posted a video about the wisp.