Here's a new one for you:
In the poll I made in PGC asking people what they look for in Pokémon games, you said that Champions should be easy enough for younger players to handle, but still have at least one or two Pokémon that can provide a good challenge for the older audiences. I mentioned the other day in a thread I made in the Gen V forum about how any Champion can be easy or hard based on your coverage, but that said, of the four "infamous" Champions (Wallace, Alder, Iris and Diantha, five if you count Iris on Challenge Mode), how well do you think they do at fitting that level you mentioned?
I apologize for the super-late response to this, but here's what I think.
I think of the four Champions you mentioned, in the case of Iris she's quite strategic for a Champion given she has a Focus Sash on that Haxorus of hers which makes you have to do actual thinking to take it down. Alder, half his team are Bug-types and that's what can make him easy to beat given he's got some common weaknesses on his team (especially Rock and Fire) so that may be why some think he isn't as challenging, but his Volcarona can still be an issue if you are unprepared.
For Diantha, she can be either very easy or very hard based on what team you have, in fact I was grinding some Pokemon against her in the Battle Chateau yesterday and her Mega Gardevoir was so rough since the ones I was training either had weakness to its moves or low Sp. Defense (which is not good news given Gardevoir is a special attacker) but I did eventually pull through, even if it meant having to endure her sheer power while using a healing item. I know some criticize Diantha for being "too easy" but it's mainly Mega Gardevoir who can make her a challenge in some situations because Megas are well, overpowered.
The one that I think is the worst is Wallace, because his team is all full of Water-types but they do have enough type diversity so that the player can't always rely on Grass or Electric-types sweeping him. For example, he has half his team take neutral damage from Grass (Tentacruel, Gyarados, Ludicolo) while Whiscash is completely immune to Electric. On the subject of his Ludicolo, its Grass-type cancels out Water's two only major weaknesses meaning you may have to carry a Bug, Poison or Flying move to exploit its weakness. While his team is monotyped, he does at least have the diversity with the types so that it makes you have to use different types to take him down.
So, I think they do well at fitting the level, because while their teams may look bad they do at least have some way to ensure they can still be a challenge under certain situations and depending on the teams you have.