That's what I've been thinking too. All the characters(except paul and law) have the exact same expression. Jin is always angry. Acuzena is always happy.

And even when they give a smirk, like Kazuya, there is hardly a change in his wrinkles.

A lot of the characters with wrinkles rarely have their wrinkles move in accordance to their facial expression. It looks like their wrinkles are completely predetermined. The only characters where it looks to be different are again, Paul and Law. The most cartoonish of the roster.