Yes, exactly. I have played this for two days in a row and found the two cards plus Vast and Intricate the biggest threat perhaps. There is hardly anything one can do against the location - passing the test is hard. In a similar fashion, unless you cancel the treachery, you might lose. That said, I am yet to lose a game out of eight played (all 2-player, solo may be harder here, not sure).
However, I still think quests can kick one's butt, often when you adjust your deck - or pick one - to a certain quest, you might actually get weaker for another.
And as for the player cards, true, there are some great ones coming up but I still think if there be a poll for top 10, core set may get more than a half.