Sorry for other people who already figured this out, but I only just got it in the last comic.
The ease of a path refers to the amount of Numbers that Fate needs to borrow to achieve its outcome. The more Numbers Fate need borrow to force an outcome, the worse off the side becomes as a whole. Choosing a path that lessens the need to borrow Numbers, allows them to remain where they should making it the "easy path" for the side as a whole, or the individual in non-Fated actions.
You know, that's probably about the simplest, and most effecient way of stating that mechanic possible. I think there is more to it that just that, but at the heart I think you are on the right track. Fate is marching towards a certain destination and it WILL make the necisary event occure, Zero must still be paid, but Fate can force others to pay it's debts. Ergo, the fewer numbers that Fate has to borrow the easier the path is over all, that would explain why the people that try to over cater to Fate end up making things worse for themselves. They have pulled too far tot he OTHER extreme and are again forcing Fate to borrow numbers.