The problem delves suffer from is repetition. Shark Teeth Grotto and Bahara's Tomb are perfect examples. Both are beautifully designed. The first couple of times through are fun. But the dailies end up ruining them. They are far from wayshrines, they are very long, and the daily has you go to the end to fetch the objective.

On the other side are lazily designed delves that exist solely for fetch missions. Faun's Thicket and Shadowgreen are good examples. You literally run in circles to complete the quest and later the dailies. Vale of Revelry is the shorter version of both and is more tolerable.

The one thing in the new delves that I can not stand is when they make getting the skyshard an ordeal. I think its Bloodrun Cave in Blackwood where you had to find the secret passage to get the skyshard. Just stop doing that.