Second thing is that it gives the game more depth in terms of deckbuilding, since we also have to consider the limited space on back row, possible row effects etc.
In my opionen you loose depth at deckbuilding, because of all cards agile, you dont have to focus at melee or ranged, besides effects. In the worst case scenario you loose some points, by not placing them optimal. You can basically place most of the cards everywhere.
Row locks on the other hand just force you do have a look at this problem, beause in worst carse you cant play a card at all AND have a big weakspot if your rows are overcrowded
Row-locked cards are not the solution; it doesn't give rows meaning, nor does it give players any meaningful choices.
I think, that the two sides in this discussion have different definitions of "meaning". For me it is "impact", lorewise as well as gameplay. So if you choose a wrong row (in deckbuilder beforehand) you lose. So if your deck isnt flexible enough, you have a big disadvantage against some decks (depend on meta). This is more the strategic approach.
You on the othe rhand want that flexibility right at a coremechanic, where you dont have to pay the price by "weaken" your deck. You want some right-now decisions, more like a tactician.
So the question is, what do we want more? A strategy- or a tactic-game?
The only "meaning" it gives to rows is "the row where I have to play my melee/ranged cards". That isn't a real meaning, not in the sense that's sought.
Just a good example of what i call impact. You win or lose, just because it isnt unimportant, which row you play cards. But if you can avoid this easily, this impact vanishes completely as well as the meaning of it.
Back to Starter-suggestion: I dont think a row effect should be set in the row itself. I am agree at the point, that this would be improve the meaning of row, but not as much as you think it would. You just buff your average point per round, thats all. Besides that, you still have to balance engines and many others cards, because 2 armor isnt nothing and in worst case the meta just shifts from removal to engine, because you cant kill engines anyway. But if balanced correctly it would be still an improvement to now, but also still less effective in the regard of "meaning" (in my sense) then row-locks.
Btw i think you need much more than 66% of all Bodycards to be row locked, top have good impact for the game