Yorvo was basically uncastable on curve because of the cost. Garruk's Harbinger maintains the 4 power matters theme and brings some conditional card draw.
Nylea, God of the Hunt is going to be the new commander. She shouldn't be as oppressive as Rhonas but will still be a powerful curve topper and mana sink. If Nylea is still too powerful, I'll try Goreclaw, Terror of Qal Sisma.