It's one of those mods that once you've discovered, you really can't live without.
Eh, I think it can be replaced with Logistics Pipes.
-Really, Logistics Pipes are 10x better than RP. Open source here too:
https://github.com/RS485/LogisticsPipes
-Frames would be missed, but they're buggy, and Steve's Carts + Quarries do 80% of what people use them for anyway (Mining..... Flying ships being the other 20%).
-Volcanos would not be missed at all. People have way more problems with their generation than they are worth.
-Marble/basalt would be mildly missed, but Xycraft may have that covered.
-The circuits and wire would be missed, but they cause just as many issues as they solve. However, both circuits and wire would be missed greatly, until Minecraft re-does the redstone mechanics or invents wire.
-Transposers would be missed, but we'd just go back to Obsidian Pipes.
IMO, the laziness of Eloraam is stifling innovation. Until she officially goes AWOL, all the developers are assuming she has the pipes market cornered.