Quick Concept - "Rock Man of AD Assassin Countering"

This is a very rough draft of a new champion concept, to see what people think or how you would improve / change it before I start refining it.

He is a rock guy, like a living golem. He's intended to be a "hard" counter to AD assassins in the Mid or Top lane while still being an offensive threat, like a Galio. He can turn his lane into a mine-field, making it dangerous to approach him or Last Hit. Especially after level 6, the trademark all-in / tower dive of many AD assassins can go fatally wrong as he will literally blow up in their faces.

auto - melee fists

p - Geomancy: casting basic abilities grants stacking shield for 3 seconds. +(AP Ratio) Armor and +(AP Ratio) M. Dmg on-hit while shield holds.

q - Rock Toss: Throw a small boulder through the air to target location, deal damage to enemies hit (Small radius). Boulder stays at that location, max 3/4/5/6/7 at a time. Mana: 40 - CD: 8/7/6/5/4 Seconds

w - Bravely Forward: passive: gains +2/3/4/5/6 flat magic pen on each auto attack, stacking 5 times. active: burst of movement speed + attack speed Mana: 50 - CD: 15 Seconds

e - Rock Detonate: Targeted boulder explodes, dealing damage in an AOE and slowing. Mana: 50/55/60/65/70 - CD: 2 Seconds

r - Force of Nature: Spirit submerges into the earth, leaving his body as a statue that detonates and slows after 1/0.75/0.5 second. Reforms at base; while he is reforming and for 5 seconds afterwards, Rock Detonate can be cast at global range + more violent explosions (larger AOE and damage). Mana: 100 - CD: 3 Minutes