Harmony - Troop Symmetry

we need to achieve a version where logic and interest go hand in hand.

The only option is to select the logical ones from the interesting ones. Because it is much more difficult to get something interesting from something logical, which is what we see. In your description, of the significant perks, dragons can only have Child of Light and Blind. Where are the interesting combinations here? For example, regeneration + initiative could work well with blind.