This is totally insane.
It massively increases the power of certain heroes, makes other heroes totally obsolete (ie, Boril costume), and makes certain defensive formations vastly better than others.
Choosing different formations should be slightly better than others; with heroes such as Boril or Brynhild in the middle, the new formations are vastly stronger than others, and these heroes become enormously better (as stated before, more like 5 star than 4 star heroes).
This is extremely poorly thought out, and simply makes the game a lot less fun to play.