I never thought of Hawks as a "borrower", so I don't really know what you're talking about.
I tend to see Hawks' whole career that way — a director who is constantly borrowing and reinventing (that's key) elements from past films, whether by other directors (Maltese Falcon to The Big Sleep and Casablanca to To Have and Have Not are the obvious examples) or by himself (Rio Bravo to El Dorado to Rio Lobo).
He's very open about this kind of "stealing" in interviews (that's his word for it), prone to say things like:
And if a director has a story that he likes and he tells it, very often he looks at the picture and says, "I could do that better if I did it again," so I'd do it again. I'll keep on doing them, in a different way. I'm not a damn bit interested in whether somebody thinks [El Dorado] is a copy of [Rio Bravo], because the copy made more money than the original, and I was very pleased with it.
He's the best.
pixote
I'm with you on the second type of borrowing, for sure, it's one of the strongest arguments for him as an auteur. But his working within (and reworking) genres is hardly the kind of thing Tarantino is accused of. Sure,
Casablanca and
To Have have the same general premise (Bogart persuaded to join WW2) but that's about it. If anything, the Hawks film is a response to the previous work (as is the case with
Maltese Falcon and
The Big Sleep and
High Noon and
Rio Bravo). Tarantino's not being charged with responding to previous works, but lifting parts of them wholesale into his own films.