Bone plating feels bad to play against
I think the 45s cooldown is too short for how good the rune is. 60 damage in the early game is a lot and if you are playing a melee champion against a ranged one who has this rune it's really hard to properly trade in the 45s window when bone plating is on cooldown. I think that bone plating's cooldown should be based on champion level, something like 80-45s.