User blog comment:Darksusanoo/(Champion Rework) Syndra, the Dark Sovereign/@comment-24948509-20150729185907/@comment-1920550-20150729211442

The base damage is gutted and the cooldown is higher at early levels. Plus the passive bonus is to allow you cast and maintain as many spheres as possible. And the passive AP gain (the entire passive actually) is made to fuel Syndra's lategame and create the idea of limitless potential which should be her core fantasy. Fiora for instance is being reworked because her kit doesn't match her theme. The way i found to justify the power of her passive is by severely reducing her early game power and transition that into lategame through her passive.

In the late season 4 Riot remaked that they we're planning on shifting some of Syndra's power from her base spells into her passive and shift her into a more lategame approach, but they never got to do that.