While canned cat food is still processed, you could boost the nutritional value of canned cat food by adding various supplements. Also, canned food contains a high percentage of moisture which is important for a cat's well being. Rooney made it a point of burying the nasty stuff before he walked away. Pumpkin wouldn't come anywhere near it. Pet food companies do a good job in the manufacture of cat food.
Palatability is the important thing.
If a cat won't eat the food, the owner won't buy it. A can of Fancy Feast has a higher palatability-factor than a can of Petguard. This is due to the artificial flavorings added to the Fancy Feast. Artificial flavorings are usually not added to natural brands of cat food like Petguard. Compared to Fancy Feast, Petguard is a bland food.