I'm not convinced. If you look at other sides, yes, they have great backlines, but no one has someone like Ronaldo to break through them. AFAIC you have the best frontline and that sure counts for something.
Your core three in defence aren't the fanciest names but they are rock solid, Cabrini was a cracking player and the only leftbacks better than him aren't available and also TPs (actually, you have a "lost TP point there" which could go towards the midfield without having to touch Ronaldo). The only team that could target Jorginho/Serginho or Bessonov is Aldo's and I can't think of anyone available out there who would have him in his pocket (edit: Thuram, but feck dropping Ron for it). He isn't even targetting a fullback but probing across the frontline anyway
You could do with another non-TP midfielder like Effenberg or Simeone but that's really it (or a good LB to transfer the TPs to midfield if needs be).