The way I see it is that it's not they have to be broken or suffer per se, but that they have to live and that comes as a by-product (but not the only one). To express and channel creation that approaches the divine they have to live a life of exploring both worlds: the external and the internal.

How can one borrow or channel the act of creation from God to create worlds, moments and feelings without having seen or experienced a variety of them? Without having lived?

Suffering and brokenness is just part of the depth of living that tends to produce great art. So is happiness and wholesomeness though.