Here are my suggestions for future updates:
Relations
Non aggression pact
Show if a tile is occupied (during war)
terrain in alliance and puppet map mode
merge alliance and puppet map modes (puppets are lighter colours of alliances rather than just lines)
formable countries (if it gets enough tiles)
if a nation revolts from another, it should automatically declare war on the parent nation
Ability of the AI to release nations as puppets to reduce revolt chance