The title of champion is not something to be taken lightly on any account, Iris never truly showed she could handle the weight of it, if anything it made her look more like a martyr, not just to Cynthia but also to Ash, who beat her at her own element (kind of a shame he can't seem to do that against Misty), and she was the first regional champion he took down as a result.
The point that i've been trying to make is, if one truly cared about Iris being champion, you'd want to see her do something impressive on screen that's worthy of the champion title, but we never got that, Haxorus's showing against Cynthia's Garchomp doesn't cut it, we need to see her actually win with her talents, not come up short in one of 2 battles that she ultimately lost, because everyone else in the masters 8 had moments that showed they were worthy of being champion outside of this tournament setting, Iris never got that.
I'm not as hardcore of a fan of hers as others are, but even I didn't like how the writers treated her in JN's, she did not need to become champion in order to reach her anime goal, just because she did in the games doesn't mean it needs to be the same in the anime, and I felt she was fine in BW, she never annoyed me.
If someone who says they are a fan of her, doesn't care about how she's treated, it's gonna make me question why, but if you want me to stop then I will.