Oregano quantities tend to vary pretty substantially from place to place. Of the two legendary pizzerias in my area, one is heavy handed, the other light.
Personally, I feel that the primary flavor that should hit you when you taste a sauce should be tomato, not oregano (or anything else). The tomato is the star, everything else is a bit player.
As far as consistency goes, I usually add some water to my puree, but it wouldn't surprise me if there were pizzerias using puree straight. As long as it's a quality puree that's still brightly colored/flavored with minimal cooking, it should still make a good pie.
And, although a good pasta sauce, can, in a pinch, work on pizza, a good pizza sauce is usually inedible on pasta.