Honestly, I've only heard complaints about them removing spying on allies. Maybe my sample.is biased, but I dislike it - disrupting an ally's CV or SV becomes nigh in impossible unless you choose to not renew the alliance etc. I'd like that ability to return, perhaps with enhanced grievances if you get caught or something. Maybe it provides your "ally" a a way to prematurely exit the alliance as well. But being locked out of spying in allies is frustrating.
Theb to have them be able to freely attack your CS...well, the Americans didn't like it when the British wanted to take the Suez.