Yeah, I can see that, though I suppose the complaints come from the fact that Ash was a brat with ego problems, but so was nearly EVERYONE in Kanto, so Ash sometimes being the only one to be punished and have to learn sometimes felt like a double standard (even if again, Misty didn't always get off scot free, especially in most of her earlier spotlight episodes which often had the same 'pride before fall' element to them).
Iris I think was relatively less of a standoffish jerk about it than Misty, more just a braggart, but yeah the lack of as much chemistry and maybe not getting humbled as often as she should have let it down a bit, it could have worked even with a tamer Ash, but ultimately it relied too much on that catchphrase (I don't know how much of the sarcasm from the OS is just from the dub however). That said Iris did at least get more ongoing development than Misty and didn't fizzle out in activity. She also worked out a lot more of her team's issues onscreen.
Actually Iris and Kiawe might stand as the nearest to fully realised takes on Brock and Misty, being two of the most active companions in the newer series and getting at least consistent smidgeons of involvement throughout their respective series.