I have been very fortunate to work with the musicians I like to work with, so there are no extra challenges for me. I always value their suggestions for performing issues (for example, the choreography of hands in piano writing) or even musical suggestions regarding the composition.
I believe the greatest challenge for today’s composers is that contemporary classical music is still not seen as an undeniable part of the classical music world. Worshipping the great masters of the past has been for a long time the main aspiration for musicians all over the world. But a lot is moving in an exciting direction right now.