I don't like how they didn't use the original Ymir from Norse myth. Ymir was the first being to exist, and he was the most powerful god, and he had two cows from which he sucked milk from their udders, and the cows licked salt from rocks to keep producing milk, and....
Now I understand why they changed it...
Classic Thor? Hmmm, it would be a hard-fought battle and they probably wouldn't take it. Current Thor, without breaking a sweat.
None of the Norse gods are written like they were in mythology. Thor was a jackass in mythology, lol. He's just as likely to beat the crap out of you with Mjolnir as he is to save you from villains.