Well, Goro was the Crown Prince of the Shokan, which I'd think makes him the top dog. Dunno much about Kintaro prior to MK2, but Goro had won the previous 9 tournaments, as well as defeated the original Kung Lao, so I tend to think he's probably the better fighter.
As to Motaro, he was supposed to have gotten beaten by Sheeva, and I'm pretty sure Goro's tougher than her.
Kintaro. His MK II Bio says that he is not only more agile than Goro, but stronger. He is also taller than Goro too. Goro is a prince by blood right. Kintaro just happens to lack the royal blood. There is also the thing with him being Shao Kahn's top dog.
Shouldn't it be obvious by now that Gamefaqs only exists to ruin your favorite series for you and make you hate all games in general?
I'd think it's Goro, since he was the one chosen by Shang Tsung and Shao Kahn to go to Earthrealm to fight The Great Kung Lao, also Goro only 'apparently' died, while Kintaro died for real, and Motaro is no contest the weakest since he was killed by Sheeva who was in turn killed by Kano.