My biggest problem with Syndra, aside from her joke of a passive really boils down to her Ultimate. I could go on a long dissertation about it, and wah wah wah. But.. how about this?
Syndra gains an extra ball floating around her for every rank put into her Ultimate? With 3 being at Rank 1. (or 4). Right now, I feel that Syndra's damage potential is severely wasted by the fact that she needs to have a high CDR to maximize the amount of spheres she has around her, and needs to be in a rather close proximity to them to utilize them for her Ult. That alone feels wonky as hell.
Also consider the fact that since each ball has to do it's damage individually, it's not all front loaded damage that takes a hit from MR. It's each individual attack. Which has the potential of being a very weak ultimate without building items to directly affect the character's abilities.
I also support the idea of having the spheres damage people infront of them as they move to the target.