Well, I found an easy way to return the game to a semblance of its original challenge level: consider orange your new "on level" content.
Today, I couldn't bear waiting any more, and so even though Rufaniel was only level 44, I took her to Eregion and did the first round of Gwingris quests (but no tasks, since the task board considers her too low to give her quests). The quests were all orange; the enemies were all either orange or red.
It felt... remarkably like playing Galadhalion back in the old Shadows of Angmar days. Rufaniel held her own for the most part, but that was mostly because I've become a better player than I was then. But just in terms of sheer game mechanics, the amount of hurt I could lay on the monsters, the amount of hurt they laid on me, etc., it felt like the original LotRO.
It was fun for a challenge, and I'm pleased I could get through it all... but I'm very glad the game's not like that by default any more! Being able to choose the difficulty level is a great thing.