Well, It's a simple game. Everything about the game is so simple. Story, combat mechanics, Char. attributes etc. Gameplay wise, nothing revolutionary. But technically it is. It gives to player a huge world to explore. I can't compare it with Oblivion or Gothic since I didin't play them but I can say that, it's much bigger than your typical RPG. Just climb a high point, and gaze the scene.
Along with this huge world, it also offers some side-activities. They are fun and really rewarding. Collecting monsters and making them to fight for you on the monster arena is the most entertaining one I think.
The game is a lengthy one. It takes up to 110 hours to beat it with the side activities.
DQ8 is one of my fave PS2 games and also one of my reasons to get a DS. It really deserves it.