A good or great sauce doesn't need to be complicated at all. When I make a true sauce I use nothing more than the best crushed tomatoes that I can find locally. Before I apply the sauce I lightly brush the dough skin with olive oil, then apply some crushed or diced garlic, add a few fresh basil leaves and then add the crushed tomatoes. Great flavor, fresh taste!
My all time favorite is to prepare the dough skin in the same manner but instead of using crushed tomato I like to use sliced of ripe, garden fresh tomato and just lay them over the dough, no need to try to get full coverage, 60 to 70% coverage is about right. In the winter when I can't get ripe tomatoes my go to is Stanislaus 74/40 Tomato Filets, and if I can't snag a can of those, my next best option is to use canned whole plum tomatoes which I tear apart with my fingers, lightly drain, and use in place of the fresh tomato slices. This approach gives you both the texture of the tomato and in my opinion, more importantly, it gives you a burst of fresh tomato flavor as you bite into those thicker pieces of tomato which you just can't get from a typical sauce.
When it comes to cooking a sauce, I am a firm believer in never cooking a pizza sauce, pasta sauce yes, but pizza sauce, never. All of those great aromas you smell when the sauce is cooking are gone forever, you will never taste them on your pizza. I do believe in making my sauce on the day prior to use to allow the flavors to release and meld, but the sauce will get all the cooking it needs when the pizza is baked. Very few pizzerias cook their sauce due to potential food safety issues as well as issues with the health department and the 4-hour rule (states that a product can remain at a temperature capable of supporting microbial growth for a maximum accumulated time of 4-hours (40 to 160F). This means that a sauce would need to be cooked to above 160 and then cooled to 40F or below all within a total accumulated time of 4-hours.
Tom Lehmann/The Dough Doctor