At the very least I believe the Krynn's Super Ability needs to be worked on. Simply because starting the game with 1 spiy shadows in potentcy compared to always get first attack or super diplomat. They are my favorite designed race except for they're super ability. Every other race has a bomb-diggity super ability except them. If not tweak their super ability then what would be even better is to tweak how you use espionage. For instance here are some idea's:
Passive:
Can See Stats
Planet Visibility
Investigate Planet
Can See Research
Missions:
Sabotage Improvement
Sabotage Building
Sabotage Project
Steal Treasury
Spread Influence
Poison Water: causes unhealthiness
Forment Unhappiness
Support planet Revolt
Steal Technology
Influence Alignment
Influence Political Party
Perform Counterespionage