more on espionage.
I'm playing my first game where I went all in on espionage points, including super spy.
I can see where you could use espionage (as its currently implemented) to retard the growth of a neighbor to out grow them and conquer them as you see fit. If it was tweaked to actually make that strategy viable, i think it might help in making a case for espionage. So perhaps:
bonus scout ship(s) for taking super spy for finding that neighbor.
all homeworlds viewable on galactic map at start.
reduce the costs of spys more so you can 'safely' invest in them before and maybe even during the cash crash.