Don't add a thing, this recipe is perfect! I agree about roasting the squash--look for that slight caramelization. Also, look up a youtube video on how to form gnocchi if you've never done it before. MOST IMPORTANTLY, these were best after sitting in the fridge for about 48 hours, on a tray covered in a floured kitchen towel. Boil them in batches, then fry in the butter sauce until they get slightly crispy (let them sit a bit, don't be anxious to turn them). Melt in your mouth yum!
I found roasting the squash instead of steaming gave a more intense flavor. A little white wine in the sauce gave a little extra flavor.