Hey Meddler. I'm the creator of the video in question. I do agree that the skill is currently working as intended (I said as much when I initially posted it, and repeated/added to those thoughts in another comment in this thread ).
I would like to touch on Syndra's current balance state. I feel that the buffs currently on PBE are going in the wrong direction, and will be bad for the health of the game. While I love Syndra, seeing her buffed then immediately nerfed again will be heartbreaking.
The short version:
Syndra has always functioned as a jack of all trades, master of none (similar to Jarvan, Lee Sin, etc). She has more damage than utility mages, and more utility than damage mages, but is less effective than either at their respective specialties. If you want good utility, you grab someone like Orianna. If you want good damage, you pick Cassiopeia. If you want something inbetween, you pick Syndra.
Currently, she has arguably the single-worst laning phase in the game. Going by the buffs on PBE, it would appear that Riot is planning to buff her late-game damage to compensate, instead of fixing her early game directly. If we're going to buff her damage enough to justify such a terrible laning phase, this is going to invalidate champions like Cassiopeia and Karthus. Why pick any damage-focused mage when you can get the same damage numbers AND utility by picking Syndra?
I'm incredibly Syndra biased would have no issue with it, but I'm not completely blind. That would be bad for the game, and it would get her re-nerfed and we'd be back to where we are now.
The long version:
Read this comment on reign of gaming and all its replies. There's really nothing more I can add to it.
http://www.reignofgaming.net/news/32228-unofficial-pbe-patch-notes-for-8-20-2015?page=2#c30