New Champion Idea - Cleo, The Maiden of the Sands

One champion kit concept that I haven't seen in LoL is a Battle Mage kind of character, (Wields a staff and does melee auto-attack damage), so I thought of a potential champion concept. I envision this character being apart of the Shurima lore and see her resembling Cleopatra from ancient Egyptian times, but, with kind of a Mulan spin. Her main color schematic is Gold with Black trim (I'm not an artist, so you really have to use your imagination here XD). Her weapon would be a staff.

I envisioned her role in LoL as a mage who really excels at bringing down tanks faster, as there isn't anyone exactly who fits that meta. This obviously can be changed. I'm no expert of what scaling and ratios make a balanced champion, so just bear with me here.

Passive - After using an ability, your next basic attack deals 50 more damage and deals (15%,20%,25%) of your current AP, for the next 5 seconds. You heal the AP damage delt. (12 Second cooldown).

Q - 1st Q (Sand Onslaught) -Dash towards the target location (600-750 units?), and deal damage in a radius upon arrival knocking up units for 0.5 seconds. Dash stops if it collides with an enemy champion first. 2nd (Sand Spray) Q -For the next 0.5, you can Activate a second Q, which pushes sand in a targeted direction dealing damage and knocking back champions who are knocked up. (For knockback distance, I'm thinking about the same as Syndra's Knockback)

W - (Sand Wall) Cleo summons a circular sand wall around her (Slightly larger than Jarven's Ulti) and the wall pushes towards Celo, the enemy's within the circular wall are pushed towards her, dealing damage.

E - (Sand Pillar) Summons a pillar, (Kinda like trundles) and around the pillar is quicksand. The enemy's within the pillar take damage each second, lose movement speed, and lose 5% armor and magic resist each second, up to 25% (too much? too little?). If an enemy is knocked back into the pillar through her second Q, the enemy is stunned for .5 seconds. The pillar would be similar to Anivia's Ulti, in the sense that it costs mana each second to keep it up. I think to balance the ability, the Mana cost could go up slightly each second.

R - (Sand Coffin) This ultimate channels for (2.5, 2, 1.5) seconds, and instantly kills a targeted champion who is below a certain level of HP (15% + 1% Per 100 AP). The range would be super close, like melee attack range, but it keeps going once it's channeling if the target leaves the radius.

In terms of builds, I can see her being similar to kayle with Attack Speed (the passive could be altered, so the more attack speed, the less the cooldown for the passive), who uses her kit to land empowered auto attacks through her passive and using the rest of her kit to ensure the enemy is within Sand Pillar so they lose Armor and MR. She could also be pure AP, and a sort of hybrid assassin like Ahri, where she tries to go for the backline.

If you guys have any comments or suggestions, I'd love to hear from you guys :).