Yorick's QoL improvements
Good improving on the Quality of Life for Yorick, hopping walkers on minions is actually less useful than many things. This might keep them more focused in lane. Unfortunately this will do nothing to address the simple fact that his skills are easy to avoid and very telegraphed, he has only one way to really control any mistwalkers and if he misses his Mourning Mist he can forget about their damage completely. There is a long list of things that need tuning, like early game graves production, the passive should be shorter, or the cooldown of Q reduced when used on minions or something. Having to choose whether I want to build up damage through graves or use it to trade with an opponent is simply denying the Yorick player options.
Which is really the issue with his whole kit, it is very static and predictable, the damage only feels good when you have walkers and land mist. . . or you can ult. Otherwise he feels lackluster in lane against everything really, and in teamfights feels like a worse Darius or Illaoi, lacking the proper sustain to survive the fights, and none of the passive damage reduction he used to have.
Since it looks like adjustments to playstyle are unlikely however, the most we can hope for is numbers adjustments on passive, movespeed bonuses on Mourning Mist, cooldown adjustments, or increased missile speed on his only way of controlling the mistwalkers. Whether those would require some sort of trade off in damage somewhere in his kit I could not say, but considering the data I have seen. . . he needs to be stronger to be even considered for play outside of silver and gold.
Maybe in 6.21. . .