Preheat the oven to 425F. Line two baking sheets with parchment paper.
Combine acorn squash and leek slices on one of the prepared baking sheets. Drizzle olive oil over top of veggies then sprinkle with garlic powder, salt, and pepper. Toss to coat veggies in oil and spices then roast in the oven until squash are tender, about 30 minutes, tossing halfway through.
Lay out pizza dough on the second prepared baking sheet. Using your finger tips, push the dough out to about a 9x13 rectangle. Bake in the oven until just barely golden, about 8-10 minutes.
Remove pizza from the oven then top with whipped cream cheese leaving a 1-inch border cheese-less as crust. Sprinkle arugula over top of cream cheese then add the roasted acorn squash and leeks. Finally, sprinkle crumbled blue cheese, rosemary leaves, red pepper flakes, and maybe a drizzle of honey over top.
Place pizza back in the oven then bake until cheese is fully melted and crust is golden, about 8-10 minutes, then slice and serve!