If you still like the scent and keep using it, honestly I don't see any reason to switch. People who say it's outdated are usually just parroting what they see online, you know how it is. Perfume isn't clothing, it doesn't expire socially just because time has passed.
What really matters is how you feel wearing it. If it makes you happy and gets compliments (or at least doesn't embarrass you), that's more than good enough. The thing is, Acqua di Gio is so popular and so well-known that some people find it boring because "everyone uses it," but that's completely different from being bad or out of style.
If at some point you feel like trying something new, it's fine to explore. But don't ditch what you have just because someone online said it's old. There are tons of new products dropping every day and people want to push them, but good quality is good quality, regardless of when it was released.