Thought this was interesting. (tl;dr getting an 18+ on EotG: cosmic engine and swooping in with rippers 1st turn is incredibly strong!) I played my first 2k game ever tonight (2nd game total) and had a lot of learning experiences. The biggest blunder of the game happened in the first 10 minutes. I am running a slann summon list with an EotG, and shadowstrike starhost with 6 rippers. I finished my set-up first, got the first turn, and went about my business in the hero phase. I rolled the cosmic engine and got 3x6 and a 5. Not thinking critically I summoned 20 skinks to better protect Slann and went into movement phase of bringing the rippers into enemy territory for a 1st turn strike. Used the 6 rippers to kill his Hag Queen on Cauldron of Blood, leading to the rippers dying to his 20 Witch Aelves. For some dumb reason, I didn't use the 18+ from the cosmic engine roll to get the double movement, double attack characteristic and wipe out both units and cripple his army. I used all 6 rippers for that one hero model, and overkilled it by 15 wounds. With the way he set up his board I could've wiped out 30 models plus his hero if I was just a little more intuitive. Plus I had 2 bastiladons that couldve ran up and got a quick 4 attacks with solar engine.
Double attack would be overkill for rippers, probably, but your other army would benefit a lot from doble movement/attacks. If you had double bastiladon, they could move 10" which is lamost certainly enough to get at shooting position and blast something with 4d6 shots each. TBH, it is a rare situation, when you won't prefere triple 6 result.