The one big challenge that end game fights have right now is that the perception of difficulty really falls apart when people take a week off and go at it for 8 hour days. The reason that savage seems so hard to most people is that they only can dedicate so many hours in a day to it, and unfortunately people forget mechanics and what not between the attempts, alongside having to deal with others not necessarily being up to speed and only having limited hours. So what gets thought of as difficulty is really just how inconsistent people are. People do not understand just how much hand holding the developers do in normal mode fights and even extreme mode. A few flashing visuals can save hours of deaths and retries. Having no time limit on the fight means people can be under performers on damage and still clear content. The real reason it takes so long for some people to clear savage is that it requires way more time than people seem to want to put into it.
