I always thought "exploring" in games was just a tool by developers to drag out the game length forcing you to wander around an overly large sandbox for half an hour between questgivers and quest locations or to look for a dungeon to do for hours then still end up finding bugger all. I much prefer a game that's linear but allows for exploration within its limits like the Silent Hill series or the Pulse section of FF13. The collectibles in Uncharted are a good example as well although I bloody suck at finding them.