Originally Posted by HexRei
Kongo is a very good kickboxer (and very accomplished and proven in that sport), his skills and style just don't translate well to MMA rules. Jack Slack wrote up a great analysis of the reasons for it here
Kongo doesn't have great technique on his kicks and his boxing leaves a lot to be desired. He does have good power and I assume he had a good Thai clinch but he never uses it in the octagon and he was accomplished in Muay Thai, not K1 style kickboxing.