In this Meta you need at LEAST two of the following to be a viable meele champion :
1)Gap closer.(reliable speed boost,dash,blink)
3)AA steroids (ad,as,crit,lifesteal, etc.)
4)Defensive steroids(Shields,resist buffs,heal)
5)Natural CC reduction (represent so far only by CC reduction or spellshields.)
Now look at those and see what Yorick has naturally ? thats right, he got nothing.He has to build everything with expensive gear, and even so he cant compare to other champions, because they will have what they built + what they have with their kit, Yorick's kit gives him nothing.That aside the crappy base stats.
Irelia has ALL.