Harmony - Troop Symmetry

Could someone please explain the developers' reasoning behind the attack and defense skills: why does defense provide a 30% bonus, while attack only provides 15%???

Because the perks in attack are much stronger, take Battle Fury or Retribution, for example, and the first one can be taken already at level 1 of attack.

Personally, I don't like this setup very much; I would prefer to see 10/20/30% attack instead of the symbolic 5/10/15, Battle Fury as a level 3 perk, not level 1, and Retribution in leadership.