Champion Concept- Qirith, The Earthen Mage

This is a champion idea for an ad based mage champion. Here it goes! Qirith, the earthen mage primary- mage home- Shurima

Passive- Magic Empowerment Qirith's auto-attacks cannot critically strike, and his attack speed is not increased. However, his attack speed is converted into cooldown reduction (max. 10% cooldown reduction), and his abilities can critically strike, adding bonus effects.

Q- Earth Shatter Cost: 30/35/40/45/50 mana cooldown: 1.5 seconds Qirith sends a rupture in the earth in a target direction. This strike explodes on impact with a unit, dealing 50/70/90/110/130 (+60% ad) physical damage to the target and surrounding units. Qirith must expend one charge to use this spell. He can have up to 3/3/4/4/5 charges, and gets a new charge every 12/11/10/9/8 seconds. If this ability were to critically strike, it deals 20% bonus damage to minions and monsters and 50% bonus damage to champions.

W- Layers of Dust Cost: 50 mana at all levels cooldown: 20 seconds at all levels Qirith gains dust each time he kills a unit, gaining 1/1/2/2/3 stacks of dust each time he kills a unit. On activation, he expends all stacks of dust to gain a shield that blocks damage equal to the amount of dust stacks he expended plus 50/60/70/80/90 health. If this spell were to critically strike, Qirith's shield increases by 50/60/70/80/90 health and he gains 20% movement speed for 1.5 seconds.

E- Stone Pillar Cost: 50/50/60/60/70 mana cooldown: 19/18/17/16/15 seconds Qirith targets a specific area. The area erupts in cracks, dealing (20% ad) physical damage to units in the area. Then, 0.5 seconds later, a stone pillar erupts from the ground, knocking up enemies in the area for 1 second and dealing (30% ad) physical damage to those units. If this ability were to critically strike, it slows enemies by 20%/25%/30%/35%/40% for 1.5 seconds after the knock-up ends.

R- Quaking Force Cost: 100 mana at all levels cooldown: 90/75/60 seconds Qirith targets an area, dealing 100/125/150 (+80% ad) physical damage to all units in the area every second for 5 seconds, as well as revealing the area. If this ability were to critically strike (which it can do once every second), it slows enemies in the area by 20%/30%/40% for 1 second and deals 50/75/100 bonus physical damage.

Please give me your thoughts on this champion down below!