Guardian Angel's | Archangel's ability heals 5 HP to any creature and costs only 1 quanta, so I think Marionette's skill cost can be reduced.
Also, I think the Marionette's skill can be amplified to all of your creatures instead of only the adjacent ones. This last suggestion doesn't make it OP comppared with PU|TU because the PU|TU can be used to copy all the effects (buffs, skills, etc) of the copied creature and not just it's attack.
I would love to see this card in the game, as it may have synergy with every buff card (specially Adrenaline
) though it makes your build more vulnerable to CC (killing the copied -maybe buffed- creature will break the Marionette's attack as well).