As A YEC, I would expect meandering canyons. In fact the question should be asked of the old earthers.
Why?
Prior to the formation of the Grand Canyon it is suggested that there was several rather large lakes (Grand and Hopi) held in place by a debris dam.
These lakes released some water that allowed a slow erosion of the not quite hard sediment carving a meandering template into the ground.
Later in time the debris dam broke suddenly and the water from the lakes rushed through the meandering channels and made the wider and deeper.
In the old earth model as the land rose up the Colorado river would have cut sideways or horizontal across the strata and not downwards as they claim. The meanders would have been impossible using the old earthers models.
The original poster of this thread is also correct. That is if the waters rapidly left the lakes with out a previous template/channel for the water to follow meanders might not occur, BUT the original poster has an even more diifficult problem explaining how the slow rising land formed meanders.