A few ideas for some stores that would really get me to spend some money in CityWalk:
A Universal 100 store, which would sell vintage tees and memorabilia based on Universal properties (like Kong, E.T., Jaws, Back to the Future, etc.) as well as their attractions, collectibles, Blu-rays, a movie poster gallery where you can purchase and print out Universal movie posters and art in a matter of minutes, and more.
As for Apparel, it'd be cool to have some stores that haven't made their way over to the rest of the country just yet like a Topshop or Uniqlo, or a Y-3 store. A new kind of Apple express concept store would be cool too.
Also, not exactly shopping but I absolutely loved the karaoke lounges in Japan where you rent a karaoke room by the hour. SO MUCH FUN and I'd love to see that come to CityWalk.