Turreus summed up my thoughts on the matter:
and to be honest? with enough experience, you don't need a one-button solution to put together a circuit; even complex devices are just a few clicks from being put together once you understand how they work. Circuit cloning would just make things easier on the lazy folks, the ones who don't even understand how it works and just pastes the codes others make. Perhaps it's elitist of me to say that, but I do think some things should take actual effort to master.
As someone who tends to mainly play engineering, I've seen this exact process happen with the supermatter setup - countless people that just join, run through the step-by-step guide on the wiki that tells you what to do but not why, think they're ready for CE because they've successfully made the engine produce power, then when something goes wrong they completely panic because it's apparent that they don't actually know a single thing about how the thing they're playing with actually works, they just followed a list of instructions that somebody else compiled for them and called it a day.
Circuit cloning via copy-paste would be the equivalent of taking the engine setup and adding a big button labeled "set up engine" that configures all the pumps and pipes for you. Sure, it'd "save work" each round, but suddenly we'd find ourselves with an engineering staff that have literally never had to engage with any engineering mechanics because one guy just solved it all in advance.