I really think the Necrozma-Dusk Mane set with Weakness Policy and Dragon Dance, Sunsteel Strike, Earthquake and Morning Sun is unhealthy and totally unbalanced. I have played about 3000 games in Random Battles (alt: Af_Tsunayoshi) and this set has almost 0 counterplay. If you end up having this pokemon in the team and you save your Dynamax for it, you have won. Why this set is broken in my opinion: if you put in Necrozma-Dusk Mane and the enemy has a disadvantage in type, you have a basically free Dragon Dance. This is fine, as it should be for like any other sweeper that needs to setup. The problem is that when you send in your counter, Necrozma can Dynamax and double its already high HP stats, gaining huge bulkiness and, in addition to that, you have access to Max Steelspike or Max Quake, boosting your defense or special defense depending on the enemy pokemon and being able to resist better to their attacks. AND, in addition to this, it has weakness policy: in order to do a decent chunk of damage on this pokemon, you have to hit it with a supereffective move, but often this isn't enough and you end up facing a Pokemon with +3 Atk, +1 Spe, and +1 Def/SpDef. You can't either stall out its Dynamax, because it will end up having your team decimated and him gaining more defense boosts, that will allow it to easily recover up after the end of the Dynamax thanks to morning sun.
This set needs to be changed: remove WP and give him leftovers, it will be A LOT more balanced.
Sorry for English guys, it's not my native language.