Can something be done to make soraka move forward in lane?
I don't think she's OP, UP, or whatever. However her being there automatically makes the lane a passive farm lane. There's no way to harass her since she's going to stand at max range behind her adc and heals them up for any harass they take while chugging 50 potions. The only way to get a kill against a soraka lane is if your jungle comes to tower dive or the enemy adc screws up positioning really horribly.
The obvious counter to soraka is to harass soraka, but no good soraka will ever be in range.