His weak point is that Dreamlands has a lot of encounters that either delay an investigator or cause him/her to be Lost in Time and Space.
Heh heh you just reminded me of a nightmare Arkham game I once heard about.
The setup: Due to the way gates opened Luck was forced to come out of a gate containing a monster He had no way of killing. Luke had the Wrack spell but Wrack only works after you enter a fight so as a result he was stuck there even when he used it. In an attempt to stay alive Luke had maxed his sneak to get 1 die to roll during a evade attempt. However Luke quickly discovered that with a maxed sneak even when he did succeed the evade check he wasn't going anywhere. Ultimately Luke decided it would be best to be knocked unconscious and take an injury but his tale of woe wasn't over yet. His injury reduced his focus of 1 to 0 (remember how he had his speed/sneak?).
In the End Luke was forced to aimlessly sneak around the Hospital for the rest of his days as the world around him crumbled.