Just wanted to write the same.
Also, spies in EU3 were much more usable and now it is like of regression. "Espionage" ideas group does not worth it at all.
EUIV made it better. It's just AI -RR that pretty much makes it useless. It was so easy to exploit in EUIII. Instant spying actions was really bad. A high BT province with decent probablity to trigger rebels? Wait to have 5 spies. Send all them at once; with bits of luck, it triggers 2/3 hudge rebel stacks in a nation at war... Or, wait that a colony with lots of natives (Africa, Indonesia) reaches around 900 colonists, provoke natives and that's one less province for AI. Just repeat again and again and AI just couldn't colonize anymore...