For starters, savage can take weeks of progression. So you expect people to spend weeks learning each and every fate and CE? That's not even workable and wouldn't get very much participation.

Secondly, you're suggesting the CEs are not already tuned like extreme or savage - they may actually be tuned that way, but you see, 75% of people in the CE can die and they will just get a resurrection, even if it's tuned like extreme or savage - which arguably, they are. What are quite challenging fights are cheesed by the fact people get resurrected by those who have done it enough to learn the mechanics, and that's intended of course.