A small (but imho very handy) feature suggestion:
Ability to use *.wz4 file location as the basis for searching assets i.e. using relative file paths. I think of it as an option in wz preferences.

It should work like this: Say, I want to share with you a file with assets (imported models, textures, *.ogg, etc.). I zip the entire project folder and send it to you. You unzip the folder, open the wz4 file and you don't have to adjust the project folder path in Document options. Assets are found automatically based on the location of the *.wz4 file.

it can already works in relative path.
When importing ressources (texture, mesh, ogg) if we don't specify an absolute path (just set the filename) it will search in the current folder.

What if we have sub-folders? And as far as I remember using Open dialog sets an absolute path to the asset in Import operator.
Those are just speculations, i can't check how it works now. Again, excuse me - I don't have wz4 within reach...

Checked that. It works only when the absolute project path is set in Project Path field in document options.