I can see him being a support, sure. Pretty OP ability if timed correctly, finally some new mechanics. Doubt he can cast twice in a teamfight even with full CDR, teamfights usually never last more than 5 seconds lul. Even if he did cast it twice, it'd have to be at the beginning and at the end of a fight, when theres like 1-2 people left alive on either side.
The fact that he's manaless already makes him instabuy/partially OP now coupled with full mitigation of projectiles and knock-up CC, he'll def be top tier.