First of all as long the SG skin didn't hit PBE, we can't be for sure.
Second, e-sport theme don't belong to the normal skin restrictions. If I skin is already in work they won't suddenly stop with it.
Third, the SKT T1 skin IS a disappointment - I mean she looks like a zombie and the animation are alright, but nothing special. And a lot of Syndra mains are the same opinion.
Fourth, as Syndra main I can tell you a secret - Syndra is fucking a bug fest. Like, I alone had 4 differents bug with her and I rarely play mid. The stutter bug has 80% chance to happen after you used your ulti and how it does feel to get minionblocked by thin air? Not enjoyable, I can promise. About randon teleporting spheres, unable to recast your W, not picking up sphere we don't even talk. X
But yeah, it's so bad we may actually get a decent skin since Justicar. I forgot, it's not like Ahri get one every year...