It seems to me that Dream Wise would allow someone to know about dreams and there interpretation similarly to the way that Omen Wise allows one to know about various omens, and Superstition Wise grants knowledge about superstitions.
I could see it as a specialty wise if it was only allowed to affect dreams that were established as having already occured, but the Dreamer Trait seems to infer that knowledge already without any skill required.
It would be nice to have some sort of overall Divination skill that would cover all types of divination skills (Astrology, Palmistry, Tea Leaves, Crystal Gazing, Card Reading, Rune Casting, ect.)
Astrology could be used as Divination, but everyone doesn’t seek their answers in the stars.