Its not obligated to show all G-Maxes i agree. I just felt that given that rose was supposed to be the villain of this arc, him not gigantamaxing was a bit underwhelming. thats about it.XY and SM didn't show off every Mega and Z-Move. Don't see why Journeys is obligated to show off every G-Max. Also, they could've just had TR repeat what they did with Drednaw.