Since Wix is mainly based on graphic editing, it'd be great if we could set layers (as in every decent graphic editor).
Where you can connect elements to a specific layer. Focus on specific layer (during the editing), easily move between layers etc... It'd make the editing so much easier.
+ having API that allows making actions on layers (hide, show, move forward, move backward etc...).
The current strip/box is not an alternative to layers.