I guess my general point is that from the first sentence of the book, Walter is Rolands ultimate adversary. Mordred has trouble controlling his bowel movements In reality, I would choose Walter to outsmart the brat. Also, his confrontation with Roland (if at happened at the very end) would further support the idea that "the ending is the same as the beginning"
I guess in the end some think Mordred is great, while others think him a waste.