Overhated - FFXIII. Maybe it wasn't what the fans wanted, and it was far too linear, but the story, characters and battle mechanics were great :3
Overrated - Assassin's Creed. You hold R1. You "stealthily" sprint up behind someone and kill them quietly. with everyone unaware by SHOVING YOUR HAND INTO THEIR BODY AND HOLDING THEIR MOUTH.
That's not stealthy