Why do you say Aaron's line of thinking is dangerous? Where and how you hike obviously affects what you consider essential, but not all of us hike on well formed trails, in the predictable weather of California.
I would not consider water purification to be essential, and in fact I've NEVER carried water purification. I also don't usually carry insulated headwear, though I do have a raincoat with hood for wind protection, and a hood on my sleeping bag.
I carry a first aid kit, and it includes stuff like migraine medicine and reflux meds. Essential? No. But lying around for a few days waiting for a migraine to pass is just not fun. Being unable to swallow because of bleeding ulcers, a real drag. Blisters? Great fun! I don't carry sunscreen, but I DO carry a broad brim hat.
I could leave the stove at home and just eat cold food, but I mainly hike for pleasure, and some of the best pleasure I have is a hot cuppa coffee to start the day, and a hot meal to finish the day. Not essential, and maybe "needy", but where do you draw the line? Why carry a sleeping bag or shelter? Just make it out of what's available like our predecessors. A nice bed of pine needles should do the trick.
There is no harm in any of the stuff that Aaron considers essential as long as he knows how to use it if needed...