After review, it seems fine. It's not stronger than Quick.
If you have only units with Impervious in a lane, it's better than Quick since the unit gets 1 attack but takes no damage.
If you have multiple units, where only the front one has Impervious, it's pointless, except against Sweepers, since the next unit takes damage instead, and unlike Quick there's no chance to kill the unit before it attacks.
After review, it seems fine. It's not stronger than Quick.