I can't help but feel that saying the game is about "how the Dragon of Dojima and Mad Dog of Shimano were born" is a bit off-base. More than anything, it's a great companion piece and lead up to Yakuza 1. Dojima, Sera, Shimano, Shinji, Kazama, and most of all Nishiki got some much needed fleshing out that makes their roles in Yakuza 1 feel so much more meaningful. I kinda dismissed Kiwami as just a fun 10th anniversary thing initially, but it's clear now how key it is to revisit the first game after 0. The really big question mark for me, though, is the near total absence of Yumi. I thought that fleshing out her relationship with Kiryu and Nishiki would be central to giving Yakuza 1 context, so... I'm pretty surprised, lol. Hard to believe we got a Sawamura-less Yakuza!
As for Kiryu and Majima in regards to them developing into the characters we were familiar with... it's kinda a mixed bag for me? I was pretty awed when I originally played the 0 demo back before the Japanese release, seeing a much more rough, violent Kiryu in the first cutscene. As it turned out, that didn't really end up manifesting itself throughout the game? Like, there were maybe one or two times when Kiryu punched guys more than he would've in 3-5, but otherwise he seemed pretty identical to me. I'd honestly give the substories more credit than the main story when it came to portraying a young Kiryu, lol. It was funny to see a much more naive, flustered, and, uh, very horny Kiryu than we were accustomed to. But to speak more positively, I liked how they developed Kiryu's reason for becoming yakuza and how he views the profession (specifically in regard to his view of Kazama).
Majima is pretty confusing for me. Maybe it's my fault looking at every major story event and asking "is this what breaks him?" when... there wasn't really a "breaking point". I still sorta have trouble seeing the through-line from 0 Majima to 1 Majima. I guess my understanding is that he thinks he isn't cut out for being the bad guy cuz he wants to protect people, and being the good guy gets him used, but... there's really more to Majima than just being morally gray, or even being crazy. In other games, he has a strange way of operating based on a respect for others built on their strength. Here it's sorta "lol fuck everything im just gonna have some fun", which doesn't really line up with the fact that I see Majima as a very determined character, just not one determined to do things others around him are. On that note, I also would've liked to have seen how Majima's fascination with Kiryu began, since we were basically thrust into their relationship as of Yakuza 1 in the post-credits scene. I hear Kiwami is, uh, a bit messy in handling Majima's character in new content so... we'll see how that goes.
As far as general story stuff goes, it's definitely one of the better recent ones. Bouncing back and forth between Kiryu and Majima's stories as they wove together ended up working out quite well. Not necessarily on board with every story beat, there was a reaaaal lot of "haha I had this planned all along and you were none the wiser" which is, eh, what can you do. It was nice having the three Dojima lieutenants as antagonists from the start to the end, but the way they were utilized was a bit odd. 4 Kuze fights spread through 16 chapters, then in the finale Majima has a climactic battle with Awano who he's never spoken to before, and Shibusawa is Kiryu's final boss as he suddenly brings out all this "I want to be the only dragon!" stuff (hmm, sounds familiar...)? It was just really odd pacing with inconsistent build-up. Certainly better than 4 and 5's final boss though lol.
oh and of course the game was fucking dope and the the directing and writing were really exciting and fun. wouldn't expect anything else from yakuza