What mechanic would you steal from another class or game?

My various Warriors absolutely want the Barbarian’s Arsenal system from the Diablo 4 beta I played at BlizzCon 2019. Frankly, it was a ton of fun and WoW really doesn’t have anything comparable — the ability to switch instantly between various weapons for specific attacks just flowed extremely well. It wouldn’t be the first time I wanted to steal a Barbarian ability from a Diablo game for World of Warcraft. Back when Diablo 3 was brand new (so back in 2012 or so) I very much wanted the Barbarian’s Might Weapons and Call of the Ancients abilities for Warriors.

Basically, just take out Warriors and add in Barbarians, that’ll do. I’d be perfectly satisfied with that change, overall. Or keep Warriors and have them and Barbarians? Hmm. It’s like having a cake yet eating another cake at the same time.

But I also think some classes in WoW would benefit from abilities other classes ended up with. Blademasters in Warcraft games had Mirror Image, an ability that ended up with Mages in WoW. I still think it’s frustrating  that Warlocks lost Metamorphosis, and I really wish a Paladin or Warrior could tank with a 2H weapon the way Death Knights can. And I think Shaman should have a Water Elemental totem — it’s always seemed weird to me that the class that specializes in elementals can’t summon a Water Elemental.

And I am sure lots of Paladins would like the Crusader’s ability to use a Shield and giant 2H weapon.

So now I ask you guys — what powers/abilities would you choose to borrow, if you could? Would you want to take the spell Eldritch Blast from D&D for your WoW Warlock? Maybe you want your Rogue to be able to use polearms, or your Druid to use axes? Hunters who could tame Elementals? What would you most like to borrow from another class, or maybe even another game, and add to your toolkit?