This been said if you ignore tasks and just kill everything that moves, up to and including mobs intended for small groups, the challenge is there and the fun too. Add to that the explorer path and you'll find an awesome game, but if you stick in completing tasks, you'll be bored to tears, you'll find your self with green tasks more often than not, you'll outlevel content and get way less exp from mob kills and so on and so forth. Basically you make the game 100% on rail, giving up that little freedom that is left.