Food gathering is a more immersive system that you mentally would have more of a visceral connection to than gathering just parts; especially if it worked like snake eater to where they would rot over time etc.That would be just different not better.
The incentive for killing here is to get parts to improve your loot, pretty fucking important on the highest difficulty, an hunger meter would just transform the game in yet another survival game and not everyone care about hunger and food gathering, have you thought about that?
We get it, you like real dinosaurs, i like them too, monster hunter is one of my favourite franchises, it doesn't mean that guerrilla made a mistake by having dinobots instead of real dinos, you just personally want a different game.
And snake eater wasnt exactly just survival because of that.
My point is the robots behaving like dinosaurs doesnt even make fucking sense. If you want dinosaurs, make dinosaurs. These motherfuckers wanted dinos, but didnt go all the way. They went for an easier design choice. It was easier to do robots, plain and simple. THATS why we have robots.
And if you have the creative IQ of a rock, then yeah, all you can envision is dinos running around being bullet sponges. This is why not everyone is a brilliant director or something, some people are just more creative than others, and others just consume.