Well, Pirlo is getting more goals and assists, always helps your rating. Assists are understandable as he'll probably be your corner kick taker and has amazing crossing + specialist SA, but Fabregas should be getting assists as well, and not sure why Pirlo is getting so many more goals than him.

Regarding other players, it's better for AMs and STs to have more attack compared to an M, Ms are supposed to be more balanced, and I believe your Ds and DMs are getting all defence and p&m, which is good as well. Only the M row I tend to balance their stats.

I also suspect it's easier for less skilled players to get a good rating because not much is expected from them.