Tonchi, there are so many threads on this that it's easier to tell you to search for them than to try to list them all. Just type in other or other storage in the search forums box above and you will get a list of threads to check. Good luck.
I've read on some thread on this forum that there is "Shrink Storage" application in the Store which somehow help destroying "Other" storage. I will try it and hopefully it will show some results.
Question: if you connect your phone to your computer via USB, what do you see? Doesn't it appear as an extra device? If Yes, then you should be able to move through the different file folders and delete whatever is in Other Storage folder, correct? Although, you may have to change the folder settings to display "Hidden" or "System" folders in order to see the Other Storage Folder. I'm curious to know because I am very close to pulling the trigger on a Lumia 928 purchase. Good Luck & Thanks.