Champion Concept: Negev (Revised)

Hello. Thank you for taking the time to look at my concept. This is a revision of what I posted a couple of days ago. I received some very helpful feedback. I changed Negev's reliance on his passive and gave him more fun and effective moves that are true to his theme. Feel free to leave more feedback on my creation. If you gave me feedback before, I would like to give you a special thanks and I hope you see this. Hope you enjoy :)

Champion Name: Negev

Visuals: Looks like a blob of sand with small eyes and a big mouth. Kinda like a brown Muk if you ever played pokemon

Role: Support/ Tank

Lane: (Main) Support, (Secondary) Top, (Secondary) Jungle

Auto attack: melee

Damage type: AP

Resource: Mana

Abilities

*Passive: Sand pools

                After Negev is hit by 5 basic attacks, he drops a small pool of sand that lasts 180 sec.  Sand pools moderately slow enemies that walk on them.  The sand pool will be destroyed if an enemy champion stands on it long enough (similar to Rek'sai tunnels).

• _Q: Sand Shot _( hits enemies in a circular area of impact, skill shot ) ( range similar to Maokai's sapling toss )

                Negev hurls a piece of himself dealing damage and dropping a sand pool on the target area.  
                ( Base damage is relatively low with moderate AP scaling )
                ( Cost is a small percentage of health )
                ( Cooldown is average)
  

• W: Mud Bomb ( hits enemies in a cone in front of Negev )

                 Negev shoots mud shots rapidly out of his mouth in a cone in front of him for 1.5 sec dealing damaged based on the time that enemies are in the area of effect.  The attack slows all enemies within the cone and coats enemy champions in mud.  1.5 sec after the attack has ended, an explosion occurs on all enemy champions coated in mud, dealing damage to all enemies within a small radius of the effected enemy champion.  The damage of the explosion is equal to the total damage the enemy champion took from the initial attack.
                 ( Base damage is relatively low with high AP scaling )
                 ( Cost is an average amount of mana )
                 ( Cooldown is average )
  

*_ E: Eruption_ ( point and click on sand pool )

                 Negev quickly travels underground to a target sand pool and erupts out of it causing damage and knocking up enemies in an area around him.  Negev heals for (0.10 Hp) and depletes the sand pool.
                 ( Base damage is on the higher side for a support tank with a moderate AP scaling )
                 ( Cost is high-ish amount of mana )
                 ( Cooldown is relatively quick )

*_ R: Sand Chasm_ ( Self cast )

                   Negev turns himself into a large raging whirlpool of sand for 4 seconds dealing damage over time to enemies within the effected area and making himself un-targetable.  Enemies are slowly pulled towards the center of the whirlpool.  Enemies near the outside experience (125/150/175) movement speed pulling towards the inside which is gradually  increased to (275/300/325) towards the center.  (Rooted or stunned enemies are still dragged towards the center.  Enemies running away from the center experience this pull as a slow, but running towards the center would be experienced as a speed boost.)  
                   ( Base damage is average with a moderate AP scaling )
                   ( Cost is average for an ult )
                   ( Cooldown is average for an ult )