Support Champion Idea

So i thought of a sort of negater support. It would be a champion based around the idea of getting rid of abilities but having huge cooldowns and decent mana costs. He will be a bulky man somewhat like braum but more of a demonic stance. He will carry a sledgehammer sort of weapon and be a descent tank.

Passive- Give you team %3-9 tenacity depending on how many teammates are close by

Q- A thin wall (about the size of a level 3 anivia wall)appears in front of you and spins at x speed, the wall cannot be passed through from either team.

W- Slam your sledgehammer into the ground and crack the earth in front of you, this area will slow and deal %current health damage per second on the terrain, it lasts 3 seconds

E-swing your sledgehammer in an arc in front of you, throwing your champion in the direction of the end of the arc a small distance and knocking back enemies

R- Create a null zone, it will be about the size of a kindred ult and no damage can be dealt or abilites used, at the end of the ult it will knock all champions back a decent distance. lasts 2 seconds

I know this may be completely unbalanced but i really want to see a ult like this and im not sure what kind of kit could work for it.