I see the core problem of this is the massively increased cost of leveling units after mid-late game, especially the units available is ever expanding. The feature you’re requesting is nice. I’d still like to see a more flexible option though... for example, infantry rares and transfer levels to and from each other. Same rarity same factory=transferable level. So the cards we draw from the crates would just be e.g. Infantry Rare Card/Air Unit Epic Card
But I understand the concept of pushing for spending
and levels aren’t everything if not too much of a difference.
However, it’ll just be nicer to be able to be more flexible.