First off, the secret of Hiroshima:
I... don't get it. Why exactly is it bad for people to know this big battleship exist exactly? Might have been something lost in translation but I don't get why everyone was so hell bent on protecting this. I'd have thought the whole smuggling Chinese people into Japan is a much bigger secret that they'd want to keep secret. That final fight should have been on the battleship itself to make things more epic... oh wait we get a badass boss battle on a ship in Yakuza 0! Another point to 0.
Now my main complaint (and judging by many other peoples comments, seems like its a popular opinion) is Iwami. The guy is a pussy, he barely gets any screen time (same complaint with Sagai) and when he revealed his tattoo I burst out laughing. He so badly tried to be intimidating but it just didn't happen for me, I mean I hated his guts, they nailed that side of him (he's a complete bastard for how he screws over several people) but as a final fight, there are several characters in this game that'd have been more deserving. Speaking of which...
Someya: He's bloody brilliant, I hated his complete lack of respect at first, and granted his personality never really changed but I grew to really like his character. He's not a good guy, but doesn't seem unlikable and totally evil as Iwami. His final fight was amazing, both visually stunning and a brilliant battle as a whole (why was he not the final boss? A fleshed out more epic battle would totally have been a great end).
Nagomo and the Hiroshima Yakuza. I grew to love all these guys the more I made it through the story. They develop nicely and I really liked how Nagomo goes from hating you to being one of my favourite support characters alongside Rikiya. I actually misread a spoiler and though Nagomo was supposed to be the final boss (which would have made 0 sense) but hey at least that didn't happen, I much prefer how his story ends.
Yuta. I liked him. Ok at first after the baby reveal he was a whiny little prick, but I guess he had a load on his mind, seeing as he just found out that not only is he a father, but also that he's the son of a Chinese mob boss. He really came into his own in the final chapter, showing up just when Kiryu needed him to save Haruka and Haruto, that was the point where he won me over.
Hirose: Loved him, granted if you saw some of the pre release media with his other outfit (black coat and gun) I kinda saw his twist coming when Jungi was killed. I did like how he was almost completely loyal to his boss, never even knowing the secret, yet still protecting it with his life. I did like how he refused to kill Nagomo though, showed he had a human side, even though he was a cold blooded killer. One thing though, either lazy righting or an intentional parallel to Kazuma in the first game, in that he killed the families of his underlings and then adopted them as his own "kids".
Jungi Han: Nice to have a shout back to Yakuza 2 with another badass Korean gangster. Its a pity they offed him when they did, as he was a great antagonist. Awesome boss theme as well!
Date & Akiyama: They are bit characters in the plot really, just there to help Kiryu out and further the plot but I'm glad they had some of the old guard appear. Date especially who was so criminally underused so it was nice to see him back Kiryu up throughout the story.
Its a real pity that Daigo, Majima and Seijima basically sat this one out. No final battle against Majima made me sad
Daigo looked pissed off at the end of the game, hopefully he finally gets his shit together and brings the hammer down on the Tojo Clan, getting things in order finally (and actually be a good chairman for once).
Gameplay wise the penultimate shipyard chapter was excellent. Big waves of enemies and an awesome boss battle to top things off (reminded me of Hamazaki's Ishin fight in places, with the smoke and all).
The final chapter lasted even longer than I expected, I thought it'd be over at the Millennium Tower so I was shocked that there was another couple of battles after this.
The Millennium Tower battle was brilliant. The game amped the action up to 11, so many huge battles that really let you flex your combat muscles accumulating with an epic boss fight. The final fight, while slightly underwhelming thanks to a pretender final boss, still managed to feel really epic thanks to the story build up. It was so satisfying to watch the cutscenes getting more and more hyped up for the final battle!
Oh, and Sagai is actually more useless than Iwami. Old geezer couldn't even floor Kiryu when he's not even fighting back, and using an iron pipe.