That is a good question but one we won't really know the answer to until we get to play the game. If it is to easy it gets boring real fast, that's why I hope its very difficult but seeing as how game developers now seem to think everything needs to be as easy as possible because they don't want to discourage anyone from playing their game, I think it is far more likely that you will be able to grab a scroll with little to no effort at all and I really do hope I am wrong about that.
Just the other day Cryptic Entertainment launched Season 8 for Star Trek Online. It puts the Federation, the Klingons, and the Romulan's against an enemy seen in one Voyager episode known as the Voth. They made the Voth, who are supposedly about 65 million years ahead of the rest of the galaxy in technology, way to easy to defeat and in beta when testers told them the Voth were too easy Cryptic said they designed them for a fresh level capped player with no reputation rewards to be a challenge to them, though 90% of their player base are full rep players and can steam roll the Voth solo.
This shows you that developers in general are so afraid of making anything challenging because they want everyone to be able to succeed and they never seem to realize that this makes their game boring to say the least.