For comparison purposes, I have also made this recipe with goat cheese. When bypassing the yogurt option, I slightly prefer goat cheese to cream cheese, but if using either one of these backups in place of the yogurt cheese, I recommend using a scant 1/2 cup and making sure to have a full cup of reserved pasta water as their consistency is thicker than that of the yogurt cheese. Realistically, if you have whole milk yogurt but no time to make the cheese, I wouldn't hesitate to simply use it as is.
Remove the skillet from the heat. Stir in the yogurt cheese and then toss in the drained pasta. Stir in enough of the reserved pasta cooking water to loosen the sauce, and reserve the rest. Check for seasoning. Need for added salt will vary based on chosen sauce, cheese, and personal preference. Toss in the arugula and grate the cheese, to taste, over top.
Notes
After removing any pasta leftovers to a container for storage, you may wish to add some of the reserved pasta cooking water to the skillet. This way, you can scrape up all the lingering sauce and drizzle it over the leftover pasta. Since the pasta continues to absorb the sauce over time, the added moisture will keep the leftovers saucier.