What if there's a doppelganger champ

Wouldn't that be interesting? Like, your stats remain the same, and your items are what you have, but your passive allows you to change to one of your opponents' champ on cooldown, hence letting you use the skills of the champ you turn into? It opens up for so much variety and forces your opponents to think twice about their team comp, otherwise they might be seeing doppelganger farming up souls as thresh then turn into a malphite with armor and ap stacked up, or they'd face a zed early game that transforms into fed jax later, or teemo shroom covering entire jungle as dopple split pushes as adc.