Pretty much the ONLY positives we found on the Wish class nightlife / bars were some fun themed drinks, more Disney-heavy decor / theming, and better areas for live music.
The Dream class is much more organized / convenient, feels more "nightlife", and the deck adult areas are also much better.
Be aware though... Disney nightlife can be hit / miss on some cruises... And is usually winding down pretty heavily by 11-11:30pm.