Similarly, we never see her blowing glass artistically. Only ever doing it when it's practical and necessary.
Maybe Ember's tempered glass fix could have been super beautiful and Gale doesn't just say it's satisfactory but maybe she calls Ember into a big fancy glass building the next day (which we can then be shown is super beautiful and is something she connects with) and be introduced to the glass boss.
E.g. The big bow down is meant to be this huge, significant thing that ties them back to their culture but also so is the blue flame. They're serving the same purpose. I'd get rid of one, probably the bow, because the blue flame is much more visual. I'd make it so that the flame shows on someone like an imprint when they are "ready", which is why Ember isn't trusted to run the shop (because her imprint hasn't shown up) but it pops up on her in the glass factory.
Wade's back story is also very weak. Like his dad dying being the reason he "goes from job to job" did absolutely nothing for the story. What we do see is that he's got love and support from his family, which could have easily been flipped to "I get to try lots of different jobs and find what's right for me". Also we only ever see him do 1 job lol. So it has zero impact on the story. Bin it.
I'd also completely cut the Vivisteria subplot. It's a tool they use to let Wade do something nice for Ember but it was super weak. It loosely tied back to the discrimination against fire people but kinda just half arsed both. Let Wade be involved in supporting Ember's art. Also it was pretty visually disappointing, considering the were some great visual moments there were in the film.
I'm generally not a huge fan of romance plots but I think they could have made it a lot more convincing why these two would fall for each other. There's a very weak, off-hand comment about how Wade "connects with people" but this isn't something that's an issue for Ember at all. It's her temper. But they tried to link the two by making her dad say "take a breath, connect" when she loses her temper but this literally does not make any sense. She connects with her parents just fine, connects with the other patrons just fine and only loses her temper when people are being complete dicks to her. So there's no actual link.
The only person she could arguably do a better job connecting with is Clod (I thought she was meaner than she needed to be). Could have been a small little moment, where she keeps his flower but teaches him to be himself, instead of a little knob. But they don't do it.
As for why the two main characters actually do like each other, I think it would have been better if Wade liked Ember for her artistic flair and she liked him for being able to accept his emotions, which is a clear strength of his. (I also didn't love that they chose to portray a man in touch with his emotions as just being a big crybaby). Could have been done in lots of ways but they could easily have set up foil moments where she reacts 1 way to something, then watches as he reacts completely differently.
(Also, the final speech she gives to make him cry was a great opportunity to for her to show how she has learned to connect with him by using her own fucking examples of things that make him cry. Not just repeating the things he said back to him, beat-for-beat).
The biggest issue with the plot overall (not the story) is the source of the leaky pipes. Like this is a massive, structural, life-threatening issue. And it's just like... a broken gate? To me, it seemed like there was meant to be a much bigger and more significant cause, given the tight deadline from the City and the very intentional mention of rust and motor oil (twice). They either needed to make it clear that cause of the issue wasn't a big deal (because at least the leak comes back later on), make the impact of the leaky pipes a lot less devastating or just remove it entirely. Make Wade actually come down as a city inspector. If not, there would have to be a big plot that involved some kind of structure or machinery but that would move too far away from what the film is actually about tbh. (Although there could have been a plot about how Element City is falling apart without the Fire people, since they got banned because it needs everyone living together harmoniously).
Another very persistent issue with the film is its incredibly patronising "tell don't show" approach, as previously mentioned. Idk if this is a reasonable suggestion but I'd just change every instance of characters needlessly saying or explaining something with an at least decent way of showing it. Pixar is usually very good at this.
The most pertinent example is the smoke readings. The mum in general has an embarrassingly insignificant part (could have made her a cooky side character tbh) but the smoke reading is a fairly important plot device. But in the key moment when Wade uses his body to focus Ember's flame, we actually have no idea what the smoke shows. This would have been significantly improved by showing the earlier couple having a somewhat brightly coloured smoke, then Ember and Wade having a super bright combo. What we get instead is very unclear, because the wisps kinda blend together but then from another angle they appear to swirl and never touch. There is no inherent sense of whether this shows a good or a bad match. (This could also easily replace the Vivisteria moment).
Related to this is the Mum being able to smell love. It's a weird plot point but contains two very annoying instances of telling: one when she finds the photo and says "but who is this boy????", like yeah no shit, we know that's what she's wondering; the other when she decides to follow Ember to dinner by sniffing the air and shouting "love!". These would have both been much better if there were a visual representation of the smell of love. We could see a purple (/whatever colour) wisp go by Mum's nose and know immediately what she was smelling.
The biggest overall criticism I have, though, is of the incredibly shallow fake immigrant narratives. It's so surface level that it doesn't do justice to real immigrant stories. Are they supposed to be Hispanic or Chinese? Maybe Indian? Really they're nothing, just a generic, catch-all, foreigner which doesn't represent anyone (for reference, as a child of immigrants, I'd connect better with a real but different culture than I did with a fake placeholder trying to represent mine). And the discrimination ultimately played very little part in the story as well. I personally would have removed the immigrant struggle and replaced it with structural struggle (things burning down etc.) and tied it back in with how people live in harmony together. The line "Element City wasn't built with Fire People in mind" is completely wasted otherwise. What did they change in the city to make it work better by the end? We saw lots of cool adaptations for other elements (like the blimps for the wind people, that was great!). At the end of the film, we should see some great adaptations for fire people. They actually did a great job showing all the really practical uses of fire and they could have built on this. (And taken a page out of ATLA's book - fire doesn't just destroy, it gives us light and life!)
And finally, the romance itself. I didn't mind it too much but I thought that the moment of Ember and Wade realising they could touch each other - hold hands and hug - was much more powerful than their final kiss. So that last scene could have been improved by them maybe realising but not fully confirming that they can touch, then finally fully embracing for the first time after the finale, rather than kissing.
Now if Pixar really wanted to make this a truly great film, I have one last suggestion that is definitely me stepping too far away from what's already there. I think they should have been very bold and actually kept it so that Ember and Wade can't touch. It would have said so much more about the nature of love and companionship if they decided that they loved each other so much that just being near one another was enough. That's what they'd been doing the whole film anyway. They could have easily added a line about how Wade feels warm near Ember and Ember feels cool near Wade. But I get that audiences wouldn't like that.
Also the sports game is just Quidditch.