I will start keeping a journal of quests, no spoilers, with a challenge rating to reflect the difficulty of these quests post-Update 9. My perspective derives from The Core rules, the basics of which are: no shrining, no xp penalty for being overlevel, no AH or brokers purchase, no House buffs, no trading anything to anyone except via chest, no repeating quests, no talking about what is coming up in a quest, no enhancement-based raise dead, plus others.
Rank will be on a scale of 1 - 10. 1 is easy-peasy; 10 is "you won't complete this quest twice in 10 runs." Working assumption: most players in the quest know it well. If a new player was with others who also didn't know the quest well, I suppose the challenge rating could be significantly higher.
1. Caverns of Korromar, elite, full party of character levels 11, 11, 11, 11, 10, 8. Thanks to Penx for skipping hard difficulty to run with us.
Challenge rating: 3.
We barely got scratched, blew through this long quest like a stiff wind, and our tank chopped down the boss in no time at all.
2. Redwillow, elite, 5-man party of character levels 8, 7, 7, 7, 6. Our 5th man joined us as we were taking the collected items back to Redwillow's camp. Some nasty fights with certain monsters who can not be intimidated. They hit consistently and hard. Then came the battle with the giants which is always interesting in Core runs.
Challenge rating: 7.
3. Waterworks, elite, full party, levels 4-6. Challenge rating 2.
4. Catacombs, elite, 5-man group, levels 4-6. Challenge rating 2.
5. Sharn, elite, 4-man group, levels 5-7. Challenge rating 2.
6. Western Threnal, elite, four-man group, character levels 11, 11, 11, 10. I might as well list the character classes specifically since some will assume it was done with a radiant servant, but they would be wrong.
Dethmed, favored soul 10 / cleric 1.
Mofeydakin, fighter 4/ rogue 4/ barbarian 3.
Thweet, wizard 9/ rogue 2.
Phunksmash, level 10 fighter.
On elite, part 3 of Western Threnal can be a tough slog at best, and a "hunt you down and cleave you into bits" nightmare at worst. We had a few moments but managed a completion without quaffing too many consummibles. We were all underlevel for the finale.
Challenge rating: 6.
Hopefully I'll be able to rank some more soon. It should give interested parties (heya Devs!) the chance to see that we need more nail-biters.