Don't try to write like Gary Gygax. Only Gygax could write like Gygax. Write like yourself first.
I think there needs to be a mix of creative writing and technical writing ability. Writing clear, coherent game rules is a real challenge, but writing evocative, engaging game examples is every bit as important.
FWIW, I take every spell, magic item, maneuver, feat, skill, item, place, monster, class, and race as examples that should feel like it has context in a larger world. I'd prefer both points of view to lead the way for the widest possible breadth of new ideas.
Plus, we shouldn't forget everything else that goes beyond prose in a game's creation.