Pulsefire Ezriel came out in 2012, Spirit guard Udyr came out in 2013, DJ sona came out in 2015 and Elementalist Lux came out in 2016. But where is the next one? They have to do it on a top laner since the others we're supp, adc, mid and jung and they only do it once a year. (or once every 2 years like they used to with ezriel and udyr.) Granted, it's going to be on Yasuo because of how mainstream he is, but looking at statistics, kennen is the most played top laner in all divisions.
Also about the Pool party skins, they started back in 2014 and they've released them yearly. But where are they? Its October and there has been no sign or hint from riot about them.
Or there have been and I'm an idiot and didn't check.