For those who can't see:
https://www.youtube.com/watch?v=a08pAACdErY
http://a.disquscdn.com/uploads/mediaembed/images/2990/4264/original.jpg
Not sure what to make of it at the moment. Taking in to account Zed's teaser it almost feels like it's hinting at an afflication or a problem these champions have that hinders them more than they might realise. The cherry blossom in Zed's teaser perhaps indicates his body trying to resist the grip of the shadows, trying desperately to keep himself above the sea of darkness he has unleashed. The smokey vapors pouring from Sona's mouth perhaps indicates her being trapped by her own music and being unable to speak truly for herself; she can only convey what she truly desires through music, and that music comes from a mysterious instrument of unknown origin. Hell it might even point to the Etwahl being the thing keeping her silent, as many have theorised over the years.
Makes me wonder what the Garen and Vi teasers are like. I'd imagine Garen's will be a shattering of body, sort of embodying Garen's lack of personal identity in favour of his feverent service to Demacia. The breaking perhaps indicates a struggle between the soldier bound to his duty and Garen himself. Vi's teaser makes me think of smoke so many it indicates her loss of identity and memories from long ago; she's lost in the fires of forget as her memories burn around her.
That second part is all just me going off though and it could be bollocks. I mean hell, I can't put together how "Deadeye" and "Jhin" would factor in aside from this being something that looks deeply in to the inner workings of people. I dunno.
EDIT: Doing some thinking here and just completely befuddled by all of this, but I'm now trending towards the idea that "Deadeye" isn't what we think it is. Similar to how little like a Bard our Bard is, I'm thinking that "Deadeye" is something more symbolic than literal. Just thoughts at this point but eh, who knows anything at this point really.