Pizza sauce should never be "sweet". People always go overboard on the sugar.
Red sauce should be savory... acidy, salty, garlicky, and herby (basil and oregano, mainly).
Since we're talking about pizza, believe it or not, one of my all-time favorite pizzas was a frozen pizza from Freschetta. It was part of their "Brick Oven" line of thin-crust pizzas, but sadly it's been discontinued.
Basically, it was a square thin-crust pizza with a garlic cream sauce, topped with a blend of fontina and asiago cheese and bacon. Fucking incredible.
Fontina is without question my favorite type of cheese. Blending it with asiago gives it a bit of punch that really works on pizza.