Just convince Riot that Yorick needs to see some LCS play and BAM we'll get that reworked ult. Considering current trends it will probably something like this.
Revenant of the Troll:
Yorick kills himself, gaining gold equal to his current worth to the enemy team. This effect does not interrupt killing sprees. After a short time (0.001 seconds) Yorick arises from the earth as a ghastly verison of Trundle, dealing 500+(100% AP)(100% AD)(100% Health) % maximum health true damage in a 600 unit radius.
Ghost Trollrick remains on the battleground for 30 Seconds, receives a 90% Cooldown reduction on all spells and gains mana equal to the cost of his last spell on cast, doubling if he hits a target and halved for each attack made by his ghosts. Dealing damage in this way increases Trollrick's active duration by 5 seconds. While in Trollrick form Yorick may also kill allies for lawls, gaining an addition 100 gold per allied kill. Killing enemies or allies while in Trollrick form refreshes the cooldown of Revenant of the Troll.
But in all seriousness, Yorick could use a little love, he's one of those champs that isn't changing with the meta nearly quickly to keep up. Hes rather hard to itemize around considering his mixed nature as well, A ult change I would say would be one of many changes i would make to him.