User blog comment:KaiserLos24/Hold on to your buffs - Riot's new teaser trailer/@comment-5077844-20150525165557

In all seriousness though:

gangplank VU seems to be unlikely (to me at least, since his model is pretty up to date in terms of animation and visuals)

If anything it's his gameplay update, but why would that get a cinematic teaser like this? And how would this relate to GP at all?

A big Cho'gath rework could be the thing, but again, why make a cinematic for that? Also, Riot never mentioned that they had any plans on making a big Cho VU or rework anytime soon.

My guess is they're just pulling another Rek'Sai...as in: Kalista is just out, here's already a new teaser.

Just think about it. The current PBE already seems lke it's ready for launch (skin splashes are there, all major buffs are out, Abyssal sceptre rework has been removed because it'S not ready yet). They could do the patch sometime this week, and then follow with the reveal of the next big (pun intended) champion reveal.

Other possibilities: Another ultimate skin? (unlikely, but when did they ever do a cinematic for a legendary skin?), Malphite VU/rework (only other thing big enough). New Zac skin (at this point I wouldn't evn be surprised if tehy decided to hype that thing into oblivion, just because it took so damn long)