I think this is stronger than it looks at first glance, but also I dont think itll make many ripples in Commander
Any abilities that trigger when a creature card is "put into the graveyard from anywhere" would still trigger, because those abilities function from the graveyard, where the card is a new object that still has the ability
You dont get to untap if the target gets removed before it resolves, so its unwise to run this out into open mana
Playing Righteous Valkyrie on turn 3 after some lifegain is a solid way to run over some opponents
Regardless, these types of decks are always enjoyable to play, as well as learning how to approach different matchups and when you should hold off on playing certain removal cards to save them for bigger threats
Not all of these new mechanics are fundamental, but its still better than if the TCG never changed at all