I'm reading ALOT of complaining that the new challenges were tooo hard to solo... on the first day. There's too many threads to post in so I'm just starting my own to reply:
Point one: They are called CHALLENGES... not lootfests. Expect to be seriously challenged.... at least at first.
Point two: They are SIX man CHALLENGE quests... soloing them should be difficult.
The devs said somewhere that they made sure they were possible to solo, but stated also that they were very hard to do so, so it is even WAI.
Tips:
1-learn teamwork
2-learn communication
3-learn from your mistakes
Now go forth and conquer!