I wasn't going to comment but this right here is simply stupid.But you'll be fine letting you yourself do the same to the AI, right?
I have played almost 600 hundred hours and in that time I have never ever made any AI country on my side give anything. Not even when I had to spend years using blockades, quick attacks, assaults and so on to prevent warscore from being low enough to give me stability hit upon decline of peace offer. The closest I ever came was offering annul treaties and that has as much to do with my country as the other. I also always try to give AI countries that actively contribute something if at all possible(and that is with me normally sending gifts/subsidies to my allies). Not to mention trying to aid offensive wars when I am not in a precarious position and avoiding breaking alliances if at all possible.
That said I think the actual problem to be fixed is making the AI capable of better understanding how the war is going so it avoids giving concessions now when it could get away with white peace by simply waiting a few months or agreeing to peace out early when it could easily get so much more and has no greater problems to worry about.
Aside from that AI give me provinces all the time in both this patch and before. Works really well for colonies and seems to require them actually wanting something from the other country(even money) otherwise they might just white peace out so perhaps there is something to be fixed there.