They would die.
Dragon Ball Ki is like Naruto Chakra. It's manifested in more than Ki attacks, but their flight, movement, physcial attacks, and LIFE. Just like with Chakra. Remove Chakra from a ninja, and the ninja dies. Same with Ki and Dragon Ball.
But, to answer what you're trying to ask (the level of Dragon Ball chracters at a pure physical level), no, no, and no. Using Physical attacks alone, Piccolo alone would have no problem solo-ing the Naruto World. In fact, he could probably do it standing still.