How many Maws can you have shaped at one time? By RAW you could shape an infinite number but i doubt that's RAI. However, limiting it to just one kinda sucks too, maybe half class level? And being able to augment it like it was an actual power would be a good addition.
Also, a minor error in Maw, it says 1d8+1.5+Int, i'm guessing that should be 1d8+(1.5xInt). It also gives two different ranges, one saying 20ft the other saying 15ft. And they're right next to each other.