When pug groups can finish 2 new top level quests on EE on the first attempt without failing even once I agree with OP - the game is too easy. I liked the days when the Sands ws introdiuced and the first completion on ANY difficulty on the server I was on took a couple of weeks. Granted that was a raid, not a regular quest but you get my drift.
One way for them to fix the challenge issue is to get rid of the imo incredibly silly scaling logic. I mean we have c/n/h/e difficulties - which is great - why ALSO add the scaling, which mainly causes the haves to only run with other haves bc not-haves slow em down AND make the quests harder? And that way the super-haves (I'm not one of them) could solo whatever epic elite they wanted for challenge/bragging rights/fun whatever.
just my two cents