She is sitting with a 46.61% winrate and 2.90% playrate, positioned 46/48. This is in Korea plat + as of today. Overall in all elo's she sits with 47% playrate with a very miniscule playrate.
Having a both low winrate and playrate shows that even the mains are not performing well on this champ. In addition, her main position is in mid whereas ryze and kayle (below her) can be played top as well. Sure she is used in LCS and pro play but we all know that pro play doesn't follow the same pattern as even challengers.
Long story short, I just wanted to point out that Syndra's passive is useless until lvl 18 and most games don't even last that long. Making it so that each one of her ability is upgraded at 6/11/16/18 would help her if not make her viable.
I've been playing a decent amount of syndra in bot games to practice her, and she seems real fun. It's a shame that playing her in a real game would be costly to my team mates.