In my opinion Undead Warlord is little bit OP. Bc you can’t counter him with single high dmg or splash dmg. You need both. And thats for example much better than Stone Elemental for same mana cost. Warlord is stronger and has stronger (not better) death ability.
Next little bit strong is Valen minion shield. Not sure how is works. But what I can see is when I took 1000 dmg and shield is 200, all 1000 dmg is absorbed to 200hp shield and after I can kill minions?