Rework Idea: Yorick Mori should be more than just a ghoul bot
I realize that the ghouls are a huge part of Yorick's identity, and I don't intend to get rid of them. However, playing Yorick has never felt fun. Even when he was strong, he simply didn't feel like a fun champ to play because all of his power was in his ghouls/ranged abilities, and none in his close-ranged brawling, despite being a melee sorta-tank. I think I might have found a compromise; by having Yorick's damage dealt heal his ghouls, and making the ghouls less easy to summon, Yorick players would have to use his close-ranged damage to keep his undead army healthy.
Passive: Unholy Covenant
Every X seconds (probably start around 15 seconds and decrease with level), Yorick's next ability will summon a ghoul. The summoned ghoul is empowered by the ability used to summon it. Ghouls heal for a small percentage of all damage dealt by Yorick (including all ghoul's damage). Each ghoul's health decays, slowly at first, but increasingly the longer it is alive.
Yorick and his ghoul's basic attacks reduce the cooldown of Unholy Covenant; this effect is increased against champions.
Q: Omen of War
Yorick gains increased movement speed towards enemy champions, and his next basic attack deals bonus physical damage. Yorick gains a small, decaying movement speed buff after attacking.
If Unholy Covenant is available, this attack will summon a ghoul with increased attack damage and speed. While the ghoul is alive, Yorick's movement speed buff is doubled.
W: Omen of Pestilence
Yorick gives himself an AoE that deals magic damage and lightly slows all nearby enemies for several seconds.
If Unholy Covenant is available, Yorick summons a ghoul at his cursor's location (within 600 range) that carries the Omen of Pestilence AoE. Omen of Pestilence's slow is increased while the ghoul is alive.
E: Omen of Famine
Yorick targets an enemy, reducing their armor. Yorick gains lifesteal for several seconds. Yorick gains an additional on-hit heal when attacking champions.
If Unholy Covenant is active, Yorick will summon a ghoul on the targeted enemy, dealing damage and healing Yorick for a percentage of the damage dealt. Yorick's ghoul also gains the lifesteal and on-hit heal. While the ghoul is alive, Yorick gains attack speed.
R: Omen of Death
Yorick summons a controllable revenant of himself or an allied champion. The revenant has a percentage of the target's base health and AD. The revenant's health will decay, slowly at first, but increasingly the longer it's alive. After 15 seconds, the revenant will die, healing the targeted ally for any HP it has left. The revenant is healed for a small percentage of the damage dealt by itself and Omen of Death's target.
If Omen of Death's target dies while the revenant is alive, the revenant is sacrificed to reanimate the target with full HP for 10 seconds.