One thing to consider is that in the current build there is no tank companion option. The companion can only be a damage dealer or a healer. That puts non-tank and non-pet classes at a disadvantage and makes meaningful testing more difficult.
From what I understand, there will be a tank companion option at release.
The delves themselves seem decently challenging due to gear scaling down, but only 4 of the 12/13 tiers are available. They are thematically quite different from one another, though personally I don’t care much for the puzzles and platforming elements in some of them. I’d have preferred delves to be more focused on just fighting lots of mobs, much like in dungeons.