When you consider the change in motivation for the series, a lot more things start to make sense. My main gripe is when they ruin characters to make them more marketable. All characters have been (and I hate this term) "disrespected" to feed Toei's pockets. Goku, who has had a lifetime's worth of experience maturing him with every saga, has been reduced to an immature and down-right stupid man-child. Can you picture Cell Saga Goku forgetting Senzu Beans or the Mafuba Seal like he did in the Zamasu arc? Heck, I wouldn't even expect teen Goku to do such a thing. Goku has always been carefree, but he's also been pretty aware, and grew up into someone who thinks a lot before making decisions. I get it. Kids like watching a dumb guy on TV who has his badass moments, but this isn't the hero we grew up admiring.
Vegeta is another character that disappointed me in Super. By the end of Z, he's completed his character arc. He's no longer chasing Goku despite being completely outclassed by him and he's dropped his pride altogether. Super backtracks on this. GT Vegeta makes a lot more sense. He only cares about getting stronger to protect the people he loves and isn't afraid of asking others for help. I guess they made this decision because a lot of fans that feel indifferent about Goku really like Vegeta, so they wanted to emphasise what they think he stands for: pride and hard work. Yes, Vegeta puts his pride aside sometimes in Super, but it's really tiring watching him go all "I will surpass Kakarot!!" when at the end of the Buu Saga he declared that he was no longer chasing him.
This is kind of similar to Future Trunks, whose entire character arc in Z was learning what it takes to be a hero, and yes, while he obviously should go back and get help when faced with an impossible foe, they went back on his character. Look at all the interactions he has in Super. You never get the impression that he's a battle-hardened warrior fighting for survival, he feels more like a bullied school-boy. That would have been fine in his first arc, but here it doesn't really work.
I felt that Super focused too heavily on these two characters. As these two are "completed" characters, it meant that there wasn't really much room for personal growth for either of them, so the show became way too heavily focused on plot points rather than a display of characters. Think about it. Disregarding power, how much did Goku or Vegeta really change over the course of Super? The lesson Whis taught Goku when Freiza blew up the Earth is one he never had a problem with before. Many characters were completely forgotten about because they simply couldn't keep up. The writers even forgot how old Trunks and Goten were! Heck, Trunks is supposed to be the same age as his future counterpart in "History of Trunks", yet he looks half his age! Tien was brought to the Tournament of Power and did absolutely nothing. Android 17 got an inexplicable power-up probably because he has a "cool" character design, so the staff most likely wanted to capitalise on that and make him relevant again. Don't get me wrong, I did enjoy watching him, it's just that he's the product of a profit-led decision.
Gohan is another character that got the short end of the stick. PlageOfGripes made a great video about Gohan and the poor writing decisions made around him during DBZ, and I agree with a lot of it.
Surely completely failing to save everyone when Buu hatched should have spurred Gohan on to keep up with his training. Gohan at this point is the strongest character in the series. Yes, I get that Gohan doesn't enjoy fighting - how could he when all his experiences have been grossly negative? But I feel as though he should have made more of an impact in the series. He's supposed to be smart right? Use that! Have Gohan use his passion for academia to become the first ki scientist or something. Let him figure out new ways to use ki to help Goku/Vegeta, teach others how to use it, etc etc etc. Instead they just shove him in a corner because they've just decided to make him a boring nerd that no one wants to watch. They probably did this due to his age. Kids projected themselves onto the character when he was around their age, but they can't really do that with a late 20s scholar, and the writers realise they've fucked up so they just keep him away.
The new characters were also disappointing. The universe 6 Saiyans are pretty universally disliked. I was somewhat interested by them initially, as it gave Vegeta something to do, but ultimately the concept failed. They weren't expanded upon, and their characters quickly became really annoying. Kaulifla was the only one I actually liked. Kabe and Kale were so annoying to watch. I know Kale is supposed to "be Broly", but my word is that concept so tiring, stupid and flat-out bad. Kabe is supposed to be Vegeta's mentee, but we only see him twice in the series ever. There were so many ways all the new characters could have gone, yet they were all bland and boring.
I honestly think that Super would be better if they gave different characters their own arc where they display who they are, how they grow, how they interact with the rest of the cast, and how they add to the overall story.