I don't think every card will have 5 levels. Just that there are better cards with better effects. Those cards have 1-5 dots which is the xp cost. There won't be 5 of every card. So for that lucky example, that is the best version and just costs 2 xp to include.
We've seen two versions of Blinding Light, one with 0 pips and one with 2 pips. But it doesn't necessarily mean there is a 1 pip version or a 3, 4, and 5 version.
I'm sure that some cards won't have multiple ranks at all. And we'll also probably see some cards have only one "rank" but still have more than 0 pips in order to limit deck building.