I haven't tried building on the rock pillars, but I really miss the old Mistland trees. There's not much room in a rock node, but an old Mistland tree...

https://steamcommunity.com/sharedfiles/filedetails/?id=2889595231

Pretty nice up top as well:

https://steamcommunity.com/sharedfiles/filedetails/?id=2616761985

and not much is getting up there:

https://steamcommunity.com/sharedfiles/filedetails/?id=2616760745

Of course, as you said, you can get huge amounts of rock very quickly from the rock pillars.

I'm actually wondering if you can build a base at the top of the Yagluth claw. I imagine Yagluth would destroy it, but I don't know that for sure. Knock down a finger or two, and it's probably all going to come down anyways, even if he can't attack it.