I'm fine with him losing One for all. But I'm not fine with him not doing absolutely everything in his power to keep being a hero, seeing how much the story wanted us to believe that no one wanted it more than he does and that no one was better suited for it (With the whole, my body moved before I could think thing).
I'm fine with him being a teacher, he's probably an amazing teacher. But I'm not fine with him immediately dropping it to become a hero again as soon as he got the mech suit, proving that that's what he actually wanted and that he once again, just like One for all, was gifted the opportunity to be a hero instead of taking action himself to fix a suit.
They could've easilyyyy cooked up a narrative that he got handed that suit as a graduation present at UA, funded by the government or some billionaire(s) as a thank you gift for saving the world and no one would've complained about that. Not a single human would've had a problem with that and thought "WOAH isn't that like super super expensive??? That should take at least 6 years to save money for!!! He should just chill and become a teacher instead."
I'm fine with him not actively being the no.1 hero in the end. I'm not fine with the story telling us from day 1 that he was gonna become the greatest hero, for it to just turn out to be "Well, he was the greatest and most important hero at one particular moment in time and it inspired a lot of people, so it technically counts!"
That's not what the story was promising and wanted us to believe was gonna happen. Everyone thought and possibly wanted that he was gonna become the next Allmight, or some variation of it. Being the greatest hero and saving everyone with a smile was all he wanted since he was a kid and there's no real reason to subvert those expectations. You know it, I know it, everyone knows it, but prefer hindsight apologizing for the writing and trying to make sense of it.
I'm fine with not getting a love interest-conclusion, it's not necessary in the first place. I'm not fine with them spoon feeding us hints like 200 times throughout the story that Deku and Uraraka was in love with each other and would be a great couple. It's both lazy and dishonest to create a plot thread and invest that many hints to it if you're gonna abandon it.
I'm fine with class A not seeing each other regularly after graduating, it makes perfect sense as people grow up, move somewhere and become more busy. I'm not fine with that depressing conversation with Aizawa implying that Deku is feeling lonely and misses his friends. MHA was always a positive (to the point of being naive) and inspiring story. It took very few risks, like having extremely few character deaths relative to its violence and stakes. I usually like bittersweet endings, but not when it doesn't fit the story it's wrapping up AT ALL.
WHY go for something bittersweet and depressing in the very last chapter when you've almost never done it before? What's the point of that? In a story like this, readers deserve to have their expectations met and be rewarded for the time they've spent following this from start to finish. And more importantly, Deku, who sacrificed the greatest power in the World, to save the World, deserved as positive of an ending as possible imo. And 99% of people probably would've been happy with that.
Anyways, thank you for reading my wall of text. Have a nice day!