A Rioter (I think it was Meddler) said that they've decided to give him a Sion-scale relaunch instead of a simple kit rework. I doubt that relaunch will arrive this year, considering how long Riot took to relaunch Sion... Then again, Yorick is an easier one due to the fact that his kit is more cohesive (thematically and gameplay-wise); Sion took a while because Riot was afraid to release him without putting major thought into his kit (keeping the good parts of old Sion and making a healthy new kit) and character (old Sion had no real identity other than hard-to-kill Noxian dead guy). Yorick is supposed to be League's premier minion-master and undead gravedigger— there's more for Riot to work with and his overall "identity" is easy to piece together.