My suggestion for a Soraka rework

Passive - Soaraka gains mana regeneration for a short amount of time upon dealing any damage to enemy champions.

Q - Soaraka gains a healing and damaging aura for a few seconds. The closer she is to allies, the more they are healed. The closer she is to enemies, the more they are damaged. Soaraka gains only 75% of the healing of this ability.

W - Soraka blesses a champion for 3 seconds. This unit takes 7%/14%/21%/28%/35% reduced damage, and their health and mana are healed for 15%/25%/35%/45%/55% of damage they take (before resistances.)

E - Soraka charges up a medium ranged line-skillshot dealing magic damage to all enemies in the line. The damage increases the longer she charges, but not the range. The damage dealt also damages the enemy's Mana, based on a percentage based on rank.

R - It's fine.