A small try to back Riot for yesterday(and no I did not like the Draven Heads)
Personally i think they might have been overwhelmed by the GAZILION of new features coming our way or need fixing(Dynamic Queue, Ban system, anti flame punishment, Hextech Crafting(which still needs some work), new client, player parties, blind pick dynamic queues, Featured Game mode rotation, and i am sure i am missing more). They probably did not have enough time to make a new featured game mode and did this.
With FGM rotation coming within the next two weeks it would require a lot of resources to make a new FGM for April's fools, though I believe URF should remain a legacy gamemode along with Poro King to their respective days and not be put on rotation but that is too late now. So they just gave is this piece of "art" ... Still can't blame them after all the improvements and genuine trying. The flaming has improved I mean that is a 5 year wish we all had, and we are not appreciating it. They gave us free skins in a way that will probably not hurt their marketing, cause let's admit it they know that a lot of people will gamble a lot, by buying chests with RP, and people like to gamble, but still for those who would never pay RP it's a good thing.
I also blame Phreak, i am sure that guy found 
event funny as fuck.
