Love the idea! I think it's actually weaker than Hope, but that might be okay. In Light, for instance, one RoL will give +1 to Hope, but with this shield, any creature other than a flying Titan or a ridiculously buffed creature is going to give +1 or less to this shield.
The shield is definitely balanced as is, and it might see some use if it were coded. I do like Naesala's post above me, though, because that keeps the card at about the same power level, but differentiates it a little more from Hope.