You can get through the content relatively easily if you have solid group composition with solid equip and for new player that means going on wiki to learn what that is and spend money he does not have on heroes he is yet to unlock. Way too often I see in alliance chat ppl asking for help because they can't beat some bonus in normal mode mission or can't beat the mission itself. There are things like boss hitting for 400 aoe on 8s cooldown with health pools being 500-600 on average, chain pulled groups with 20-30 mobs that wipe you in seconds, constant interrupting, energy denial etc. And that is no raid content or group content.
GW2 can be completelly different, but right now what I would be worried about is ANET making GW2 with same difficulty GW1 has and again I am talking about the story mode here. The explorable mode while there should be easier and harder dungs can be tuned really high. Especially since wiping in them does not mean game over like in GW1, that alone makes them quite a bit easier by default.