I would be surprised if your ideal pizza sauce came out of a can. Especially a can labeled tomatoes.
If it's watery then yeah draining would remove water. If it's lacking tomato flavor, then yeah, a different tomato brand might have more tomato flavor. If its spice flavor your after, then yeah your gonna need spices. Other flavors might be oily, vinegary, or perhaps tart (acidic).
I've only made my first pizza sauces this past month ( they weren't stellar). My thoughts on sauce:
-The sauce should match the other ingredients. It should compliment the dough flavor, as well as the cheese and topping. You can have a great sauce that blends good with olives toppings, but is kinda bland on a plain cheese pizza.
-Why is it that ready-made pizza sauce in a can is awful? Perhaps the key is fresh ingredients.. This leads me to believe that recipes that start with browning garlic and onions in a pan and using fresh herbs like basil and oregano would be better.
- my first attempt at sauce I hated. It really wasn't the sauces fault though because the cheese was awful. The dough was bad too. It never had a shot at being good because the pizza on a whole sucked. I would say sauce is a pretty minor ingredient in pizza. You could almost get away with having no sauce and if the rest of the pizza was great, then it would still be a great pizza unlike not having the other ingredients.
-I think I am gonna focus on making recipes that include dough, sauce, cheese, baking temp/surface etc... All the peticulars.
-If I am not sure what flavor sauce I am after I think of a commercial example of sauce I like and search these forums for a clone recipe.