This holy bonus is a very cool idea. Generally speaking, alteration of units stats depending of external factors are always a nice twist in games, and are very appreciated from the players (well, the ones I know). In Dominions II there will be national themes, and Holy Bonus. good, very good !!!
I must confess that a big reason why I really like dominions, tons of intricate mechanisms aside, is that the devs have many good ideas. Take for example Age of W... the game is good, true, but speaking of game design on the other hand, it is far less imaginative. Kinda like a vanilla ice cream, compared to dominions which would have exotic flavors