What has Goku really done as an Oozaru??? Stepped on some houses, stomped around, I don't even remember him shooting his mouth beam.
Naruto as a four tails had a roar that damaged a large area around him, and the Chakra Ball is the fight ender, it made a huge crater next to Konoha, which was already destroyed. He also has a speed and durability advantage. Where an Oozaru can get cut by a normal katana, Orochimaru's Kusanagi Blade didn't even get through the blood shroud, and he shot it out of his mouth with enough force to knock the 4 tails very far away. He also reversed the effects of Shinra Tensei, and pushed it back on Pain.
We only really got to see Goku rampage as an Oozaru once, early on in the series. That form would lose. However, if this was Goku at the point where he fought Piccolo Daimao, or even in the 22nd Budokai, who went Oozaru he would stomp
Goku, as an Oozaru is basically featless, he wasn't even able to use his mouth beam. All he did was stomp around and act retarded. Also, Vegeta, who was much stronger than Goku, got his tail cut off 6 Tails Naruto on the other hand has a blood shroud that tanked the Kusanagi Sword, and he can shoot the Chakra Ball, which is equivalent to one of the energy attacks used later in DBZ(Super saiyans and all that). He also reversed Shinra Tensai.
Goku loses. He was a mere child when he turned into an oozaru and was nowhere near the size of the oozaru's that appeared later. All he has are unimpressive strength feats.
Look, he's not even that big compared compared to Yamcha. Shukaku, Three Tails etc are all bigger and probably stronger than him, Naruto can take this no problem.
Shenron wasn't that big in his first appearance either. I don't believe Toriyama had really decided yet on how big he wanted his larger characters to be in relation to every one else.
If he had drawn that same form of Oozaru Goku now, no doubt he'd be as big as any other Oozaru.
That'd make sense, if that actually WERE on-panel evidence. Goku, when he first transformed, was about 12 years old, whereas Gohan later on transformed when he was only four. And Oozaru Gohan was clearly depicted as being bigger than how Oozaru Goku was in his first appearance. Age clearly has nothing to do with size.
Size still doesn't matter, Naruto has an impenetrable blood shroud, an area effect roar, the compressed chakra ball, insane speed, what can Goku really do besides lose?
Are you serious, putting a featless monkey up against an elemental force??
Naruto's 6 tailed chakra ball devastaed an area the size of konoha, and he resisted the effect of the same attack that turned konoha into a parking lot, he even reversed it on Pain. He also has a blood shroud of impenetrable, dense chakra.
Tell me, what can Goku do, besides die a horrible death?