It seems to be getting some vindication lately, but the 2008 Speed Racer film by the Wachowskis was absolutely amazing, in my opinion, but it was a critical and box office failure at the time. Not only did it capture the inherent silliness and cartoonishness of the original Speed Racer anime, but it elevated that feeling through its visuals and overall escalation of its over-the-top style. I'm also a huge fan of the comedic style of "playing absolutely ridiculous situations completely seriously" which is exemplified by something like Airplane! and pulled off well in Speed Racer and I feel like the fact that it was supposed to be comedic was lost on a lot of the critics at the time. And it's the kind of playful humor where I feel like the Wachowskis are actually genuine fans of the source material and are laughing along with the fans instead of trying to mock the source and looking at the audience and saying "This is so stupid, isn't it?" (but like, in a mean way, not in a friendly way)
What bothers me about this criticism is that The Last Airbender literally had Iroh, in his 50s, make a complete 180 from being a conquering general to a pacifist teashop owner. In my opinion, that's a far more drastic change than Toph went through, and he didn't even have the excuse of having not gone through puberty yet.
Other than that, I think the fact that I have pretty morally grey views of both the police and Toph makes it easier for me to see her possibly going in that direction. The argument that Toph is a free-spirit and dislikes authority doesn't really go against my view of people who become cops. It kinda comes off as naive to me, to suggest that everyone who becomes a cop inherently values strict law and order instead of just wanting to be in a position where they are the ones in charge. I can definitely see Toph's childhood attitude eventually developing into "If I was in charge, then no one can tell me what to do." Or even "I was a mess as a kid. Someone like me should have been reined in." I don't consider either of these beliefs to be especially noble, or even "good," but like I said, I've always viewed Toph as a bit more grey in morals than the rest of the Gaang - and that's one of the reasons I really appreciated her as a character.