I found this:
[Have we ever figured out how stat boosts are calculated when defending? - #2 by Garanwyn]
@Guvnor do you know if 
still true?
If this is still the case then, minions are going to have more impact on defense.
While on attack they feel like they’re just dragging out the inevitable beating.
Plus… on attack your wings aren’t protected from the AI as the defense is protected from tiles. Which gives some Creedence to Noor if the sparrow survives and clears a wing’s triple stack.
That feels pretty good.
Which for me is about 1 out of 5 matches…
And I suppose that number might increase if I ascend Noor but… I just can’t justify it. My other attack squads have genuine impact