Can I export my world from the Wii U version of Minecraft onto a USB Stick?

1. Turn your Wii U off.
2. Insert USB Stick.
3. Wii U will ask you to format the stick. Click on Format. (ALL DATA ON THE STICK WILL BE LOST!!!)
4. Refer to this page: http://en-americas-support.nintendo.com/app/answers/detail/a_id/2439/~/how-to-move-or-copy-data-to-and-from-a-single-external-storage-device
5. Enjoy!

Also, your computer won't be able to read the USB Stick without reformatting. So you can only transfer saves thru consoles.

Any USB memory device used with a Wii U has to be formatted in a special way specifically for that Wii U. I don't have Minecraft on my console so I cannot verify this, but I highly doubt that any world created on your Wii U version of Minecraft could be exported out via USB in any way. Unfortunately, I think your world can only exist on your Wii U.

I'll be honest I've not read the entire post but this link should be of at least some value :

https://mcctoolchest.weebly.com/wii-u.html

With this tool you can convert save data from console to console. It's a bit of a hack but it's fairly simple if you can follow directions. I used this to convert my ps3 save to a wii u while I was waiting for my ps4 pro.

Long story short, you can save your world onto your usb stick and convert it to whatever console you need to that supports the game in the first place.