I like the idea of 3 drakes but I think for true impact, you're probably best stepping back and looking at where the points are freed up around that traditional starcast "core".
The thing that sticks out is the comet/SC caster absence. For me this always equates to "Celestant Prime"
So where the Kroak, Incantor/Comet, Drake, Drake list has a focus on recycling the comet - later in the game (when battle is joined) you'll get less impact from that comet - if you can even find space to land it without laying wounds on your own guys. Your Incantor will be laying on Azyrite Halo instead.
In this list, the late game has more comet potential via the scepter (which lets you choose range to keep things safe). Or you might have a match where you don't think the comet chip damage will take off a key piece so you use the Prime as assassin (with many CP for all out attack and charge rerolls - delaying when you need to declare you're using Orrery of fates and thus increasing the chances of 1 extra 3 damage attack getting through).
Spontaneously I feel like the Prime's weakness means it's a more risky list. It'll require more finesse than the comet recycling variant.