I am also at the the third and final step of this quest chain. For those who might be interested in helping, I believe this 5-person group quest in Netherstorm also gives a big chunk of Consortium rep.
Step one is easy if you have a flying mount, if a bit tedious - you need drops from voidwalker-type mobs quite near the quest giver; low drop rate, but they are plentiful in the area. Took me about about 10 minutes soloing.
Step two is very, very easy - you take a pre-programmed bombing run on a dragon around the top of a manaforge. You just sit there and spam-click an item until you get enough "hits". You don't even have to aim, there is nothing threatening you, and if you don't get enough hits the first time, you just go again. Usually takes two circuits which equals about 5 minutes.
So, all told, in about 15 minutes, you can catch up to us in the 3-part quest chain. I have seen (but not bother to read) a couple of postings by people who said they defeated Dimensius The All-Devouring with 3 or 4-person parties, so it should be pretty easy if we get a healer to join us.