After the surprise success (and authenticity to the original material) of G.I. Joe: Retaliation, Chu could be a major loss, but Rossio seems like a guy who know how to make an epic. But which Rossio will be writing, the PotC1 Rossio, or The Lone Ranger Rossio? And does he know or care anything about Masters of the Universe? I sincerely doubt it, so goodness only know how much he'll be messing around with the story.
But since a Masters of the Universe has been more or less stuck in development for a decade at this point, I'm not too worried that we're getting any closer to seeing He-Man back on the big screen. Yet.