Lost Judgment only has one tailing mission required for story and it's like the first thing you do and so far the longest of the game, tailing people seems to take less time overall and thank God, side stories do have more "mouse over stuff to see if Yagami says anything" including one annoying series of side stories about a shady detective, have no shame in saying i didn't even bother with the spy cams over the school side story and just checked a guide online.
Also, new minigames and yes, side stories based on those, not really a fan of some, the Robotics Club mini game is kinda boring and once you get to the main tournament, there is a big difficulty spike i wasn't ready for...because the initial robot model served me just fine and i find the mini game so boring i didn't even feel like investing time in getting materials to make better robots.
Oh, and the Judgment games have no Karaoke, though Lost Judgment has a new dancing minigame which is different from the one in 0 and is more like a standard rthym game.
Yagami is...of the three main characters(not counting the PSP spin-off games because i haven't played them) he is my least favorite, he is stoic a bit too much and unlike Kiryu doesn't seem to emote as much or get invested in stuff, Kiryu is a stoic man but he does react when something makes him angry, or he is near people he loves or gets invested in nerdy stuff at times almost getting child like, still love how in Yakuza Kiwami 1 he outright accepts fighting Majima if it means he won't ruin racing with toy cars for him, and even if he gets good at stuff instantly fast, it doesn't seem like he becomes the best at everything right away.
Yagami however...i guess he celebrates winning in Drone Races and smiles sometimes, but it's subdued stuff compared to Kiryu and Ichiban, and he is far less nerdy, also just seems to be instantly good at stuff, oh, he never danced before...not to worry, the first time he dances in his life he will be instantly compared to a professional dancer, oh, he never skated before...don't worry, the first time he skates in a competition he beats someone that has been skating for a while and instantly knows how to do some tricks, even when it comes to terms of getting injured, he is just...kinda too cool and stoic, like Yagami can't be too excited, can't be too scared, cartoonishly angry or anything, as if he was a standard badass action movie character...and in a way this makes him feel more generic and boring than Kiryu and Ichiban, say what you will, but when they find something they enjoy, they seem to actually become a master over time and really get into stuff rather than Yagami being like "well, i guess this is my 549th amazing skill i have that i just found out...oh well, carrying on" which is the vibe i get from him.
Maybe it's because Yagami's actor is actually famous and was so before they used his likeness for Yagami and Sega can't make him look bad and he has to be cool, professional and amazing all the time unless he gets a time to make a speech about justice and morality.