Rehashing and inspired by are different things.
There are certain elements of Journey to the West found in DB but not even Goku is similar to Wukong. Yes, monkey-like features, extending stick, perhaps a couple of early characters but everything else is not even close. So I don't think it's fair to say that is a rehash.
Judging from the initial portion of the anime Dragonball pivoted gradually from a loose adaptation of Journey to the West (with Goku as the protagonist among funny versions of traditional characters) to a more original and specific setting and plot (with Goku as the most important of many Saiyan and martial artists).