The nether has almost zero value to me. My main world I created before they added it, and I've got a massive rail network going on for transport. Building in the nether never appealed as it looks bland against trees. Assuming I'm starting a new world, then maybe I build a transport network there but no reason to live there or run about for anything more than gathering.
As for difficulty levels, I play on peaceful. The combat is easy and un-fun, random creepers blowing stuff up isn't fun, waiting for zombies to burn each morning while I wait isn't fun. There's zero value in having monsters turned on. If I want to fight monsters, then I'm playing a different game. Building is what I'm here for, not bad and basically annoying combat.