Its about time where i see it discussed once again, and i like to trow my hat into the ring for it.
My idea is easy.
You take the resin whisperer strain from the hivelard and make it better.
The ability to build thick resin structers from a distance, a plasma pool big like a drone, and hek the ability to build multipel structers at once. Basicly giving them the ability to creat a wall in a few seconds.
You could even make the fun thing of allowing them something similar to the burrower. Being that they can dig to any tile they can see. Only that unlike the burrower you could only do this on weeded ground and to weeded ground. Basicly swimming through the resin.
Maybe give them a strain that would remove there ability to place node enterily for something so powerfull the gods wouldnt even dare of it. Building strucures while being rested.
I know this is completly unballanced, but the idea of a T3 drone cast is something that comes up every so often. For a good reason, hard to make a T3 builder thats worth it but not over powerd. But i had this idea a bit ago and thought someone smarter then me migth be abel to turn this into something better. Even if its just a spliter of it that helps in the end.