Honestly, the Canyon is what you see at the canyon. There's different views and small details to pick out. Going down into the canyon I guess you get a different perspective? Spending a day jostling around on the back of a mule/donkey doesn't sound exciting to me :) There's the touristy Watch Tower, part gift shop, part observation tower over near the South East entrance
I found Utah highway 128 to be equally spectacular. Same Colorado River, same fantastic blends of oranges, reds, browns in the rock. The bonus of UT128, you can pull your camper right into a BLM rustic site along the Colorado and camp there a few days. Only way you're camping next to the Colorado in Arizona is after riding or hiking down the walls, and then you're sleeping on the ground in a tent.