I think it can be said that annexing a piece of Southern Italy is also not the optimal strategy, though. I've always wondered what considerations the AI goes through when it decides to annex a place like that. Does it realize that infamy spent on Southern Italy means that infamy can't be used to annex another place? Does it even have long-term strategies with regard to expansion?
Then again, the AI often sits at 0 infamy without annexing any places at all. I wish I had more insight into how the AI chooses that sort of thing.
I would much rather have France conquer Catalonia and the Rheinland than Puglia. That is for sure.