@Salamkrishne unfortunately I don't know much about KP Bhattarai except he used to lose elections. And, there doesn't seem to be much info about him. It may be because he is underrated as you said. He was perhaps over shadowed by the Koirala brothers.

Speaking of Bhattarai, Baburam Bhattarai is another intelligent and introvert leader. In terms of intelligence, he may be as intelligent as BP Koirala or maybe more.

http://hataru.blogspot.com/2015/10/thus-prachanda-and-bhattarai-part-their.html?m=1