Obviously this would need reworking or balancing of some cards, but I honestly feel like it would bring a ton of depth to the game, and honestly, I don't see how it would be unrealistic to have rows interact with each other.
Imagine Frigella Vido, the soldier guy, Kiera Metz, and all these other really bad cards actually being meaningful or have a higher ceiling.
Things like Rot Tosser or Tunnel Drill might have to be adjusted, but I don't think this would make the game unbalanced. You could just make Drill start at 0 damage.
It's just a thought, but I feel like it has a lot of potential. Obviously some abilities wouldn't always work to its max capacity because sometimes a unit wouldn't be directly behind or in front of a card, but I feel like that's where this change is best; it makes you think about card placement more/gives another layer to when to play something.
Maybe even units directly in front of a card on the melee row(the opponents side) could be messed with. Like a cultist that damages the unit it in front of it by 1, then boosts a unit behind it by 1. Maybe a 6-7 prov card.
Idk, this whole thing was just a shower thought, but I feel like it opens up a lot of cool interactions and potential. It might require reworking some things, but that's fine.
And if something like Whoreson Junior needs to stay at transforming two bodies, just make it say "transform both units on either side of blah blah". So some old cards could stay the same.