I'm curious because I can't stand when a champion is a single-type trainer(Lance, Wallace, and Iris) because I feel like it's not much a challenge.
The Champion is supposed to be the best in the region correct? So therefore they should be one of the hardest to battle. The challenging part of a multiple type champion is you have to strategize more in terms of what party you use and what each one's weakness is. That's why champions like Blue, Steven, Cynthia, and Alder were difficult.
HOWEVER, when the champion is only a single type, then it's just like any other gym battle where as long as you have a type in your party that is strong against them, then you can pretty much sweep them.
For me, Wallace was laughable because with a grass and an electric on my team I completely destroyed him, Lance was easy too with an ice type, and Iris disappointed me the most because I only had to heal ONCE in the entire battle and used mainly my Vaporeon(with ice moves) the whole battle.
What are your thoughts on single-type Champions?