They're easy because many players are already well overgeared for them. Personally speaking, I had quite a bit of difficulty running the story quests to unlock Leviathan (The enemy encounters in Sapsa Spawning Grounds feel as though they've been retuned to provide that challenge even at i80). But as for everything else, yes it SEEMS easy, but try running it at the base ilvl requirement or slightly higher for the challenge. Not to mention if things are too hard, progression stagnates, and players lose interest (and yes, the same could be said in opposite).