Quote from link.

We had collected some interesting wishes from DBO ファン here.

Wish 1: Can あなた help me to change someone's character like this style?
Wish 2: Can あなた let me keep the dragonballs forever?
Wish 3: I wanna watch a fight between characters from Dragon Ball and Naruto...
Wish 4: Bestowed me a flying riding 雲, クラウド as Goku's, please!
.......

So when あなた have gathered all dragonballs, what's your wish?