I agree, but want to mention that challenge isn't always specific to individual difficulty. A lot of the bad players tend to stem from the games primary focus on the self, rather than the group. It'd be good to have more content that focuses on team efforts, which for this playerbase, must be introduced slowly and in an obvious and mandatory manner. Output is important, but this game sorely lacks a focus on needing the group to be responsible, instead of just the individual player.
I actually think things would go better if 8 and 24-man content were more streamlined into a dungeon-esque situation, similar to how 24-man content is currently (which means it'd be nice to see more of it). Branched off paths that eventually come together, boss or trash mob mechanics that require interacting with something in the environment, a need for 4-8 players to run a gauntlet while the rest of the group handle the main boss, etc. Stuff that is either obvious and automatic or that requires a quick "strategy" assignment to a group. Not saying to lessen the amount of the "right-to-the-boss" type of layout we normally expect, but rather to add in a couple of the type mentioned.
CC mechanics could always make a come back in some way, with removed non-stun DR punishment in PvE (but maybe a reduced duration). Something to just bring an importance back to group coordination, rather than simply focusing on gearing up to burn down the target faster. It can still be very casual, despite a reduced need to focus on DPS numbers. That DPS output currently is clearly too much to expect according to the devs with the upcoming combat changes, so I don't really see a problem with making group focused duties fun, rather than individual output.