This scenario already played out in WoW. The devs tried to make normal dungeon content more difficult in Cataclysm, hoping that players would rise to the occasion, but instead players just gave up and complained until everything was nerfed into the ground.

You could say that's a different game and a long time ago, but the same thing has played out here in Orbonne Monastery. Orbonne was not hard, at all, but players found it so incredibly difficult many would just bail on the raid the second they saw that it popped. This eventually led to the echo buff being added and Thunder God being heavily nerfed. 90% of the Thunder God fight is just looking at the boss and standing at the front or back at the right time, but that was too much to ask for a lot of people.

Heck, half the reason people ilvl cheese alliance raids in general is because they can't do mechanics. I once had a dude begin an Orbonne run by saying "oh shit I forgot to take my gear off" and he spent the entire rest of the raid dying to literally every mechanic, every time it happened, all while constantly complaining in party chat about "OMG THIS IS SO HARD" and "I JUST WANT MY TOMESTONES WTF!!"

I would personally love if standard content were more difficult and I had the same outlook as OP years ago, but unfortunately the reality is to the contrary. The system we have now is probably the best approach, where most content is pretty easy but there are more difficult alternatives if that's what you're looking for.