This was a very interesting video. Eerily enough I've also been thinking very similar thoughts to the ones laid out here in terms of gameplay, and agree with most of everything in the broad sense.
My one bugbear is the point about hiring a better scriptwriter because I think the route to a next-generation Shenmue formula isn't necessarily underpinned by personnel changes but a more structural/mindset solution. A new writer *might* help with overall characterization and structure, but it's hard to say one way or another whether that's the solution to having a meatier story in Shenmue IV because of all the moving parts in the development that dictate the shape of the game. What might be more effective is if YsNet went into development with the mindset of focussing on the core experience above all else, and letting gameplay and story justifications intermingle and drive the project.
As an example - training minigames. If YsNet were to create advanced versions of Shenmue III's training minigames, they could be justified by Ryo having to enhance his training after losing to Lan Di and effectively make a change in gameplay a plot point. This is a dynamic the book balancing minigame achieved in Shenmue II when you think about it.
Not sure if there were many complaints about the simplicity of the minigames (in fact I seem to recall praise for the breezy arcade-lite approach to some), but they did lack a "scaled up" version once Ryo got into the higher levels, so an advanced version of the training minigames could serve that purpose while also telling the story of Ryo getting stronger. Horse stance could take some inspiration from the movie Drunken Master, where Jackie Chan's character has to perform the stance while balancing teacups on his shoulders and knees. One-inch punch could become like the Shaolin technique of punching stacks of paper pinned to a wall to harden their fists, or the "real" one-inch punch technique where there's no wind-up at all like Ryo does in the Shenmue III training minigame. There could be a new minigame where Ryo does the "sticky hands" technique on a kung fu dummy that plays like a basic DDR-like rhythm game or having to do ab crunches while suspended by his ankles, or stepping on the "plum blossom piles" you see in the village square in Bailu.
Lots of room to expand, improve, create, and integrate with the story, individual quests, and hopefully a second-generation version of the RPG stats seen in III.
I also think this tandem gameplay drives story/story drives gameplay mindset could help figure out a way of tutorialising gameplay systems without *tutorialising* them, if you get my meaning.
[WARNING - extremely long post ahead about a theoretical Shenmue IV]
As a thought exercise, I'm going to write out a collection of ideas I've had just generally thinking about the potential structure of Shenmue IV with the mindset mentioned above. It's by no means completely thought out or even a realistic expectation, but it's just to show that treating gameplay and story as a unified concern rather competing interests can yield results for both.
The game starts with a prologue sequence that recaps and expands on some points from the end of the last game and picks up with Ryo, Shenhua, and Ren on the Great Wall heading towards their destination - the cliff temple. It should introduce the story, the core characters, and some of the main mechanics. Ryo is having nightmares about Lan Di, and some kind of self-doubt is sinking in about his revenge mission - which sets up his character arc for this game, which is growing past that. We could have a callback to the campfire scene from II, but this time it's with three people and some branching dialogue trees, and perhaps this is where you reintroduce an expanded affinity system if Shenhua and Ren have a disagreement and you need to pick a side.
The next morning as they're approaching a settlement at the foot of the cliff temple they meet an old man. He recognizes Ryo as a martial artist and asks for a demonstration/sparring match. You've got a brief combat tutorial as he asks to see hand moves, leg moves, throws, dodges, parries, counters - whatever ends up in the next iteration of Shenmue's combat system. The old man is pleased with what he sees and toddles off as the crew descends into the settlement.
The settlement would act as a miniature Shenmue sandbox that introduces supplementary systems (jobs, gambling, collectibles, etc), basic training exercises (could just copy and paste Shenmue III's training minigames here for now - you'll see why shortly), some early questlines and real-world cases of employing the combat.
About a fifth (or a quarter perhaps) of the way through the game, Ryo & co. head off to the cliff temple and don't get very far as it's overrun with Chi You Men. Here we set up the villain/rival of this installment (not Lan Di because I'm presuming the rematch doesn't come until later in the story anyway, maybe Ziming), and Ryo has to fight him. In true Shenmue fashion, Ryo gets his ass kicked, but it goes much further than it ever has before. Ryo is seriously injured (dislocated arm maybe?) and left for dead (let's say he gets done like Big Boss in MGS3 and is thrown into a ravine). Shenhua and Ren escape, but only just. It's a big dramatic moment to put some punctuation on the end of the training wheels portion of Shenmue IV.
It's days later, and fate has smiled on Ryo as he wakes up alive, but not particularly well, in a rustic hut. Somehow he survived the fall, avoided drowning, and was fished out of the river (coincidentally, Taxia village in Fujian province - where the tulous are - has a river running through it). Who saved his life and nursed him back to health? It's the old man from the Great Wall. There's some explanation/exposition about Ryo's situation, and we're given the mission statement for the rest of the game: become a better martial artist and uncover the mystery of the cliff temple + Chi You Men. The old man reveals six martial artists in the region might be able to help him (doesn't have to be six, of course), but Ryo has to seek them out himself - and in doing so will unlock new training minigames, sparring opportunities, new techniques and moves that can be unlocked via story/side mission tutorials and/or a skill tree system, not unlike the one originally planned for III.
This is the central mission storyline of Shenmue IV that runs in tandem with other critical path missions that flesh out the gameplay, characters, and story. I would love if YsNet could take a bold step towards evolving the non-linear questing elements from the first two games, so you have a choice of objectives and freedom to pick in which order you accomplish them. Straight out of the old man's hut the player can be faced with a decision of immediately going to ask about local martial arts masters, or trying to find out what happened to Shenhua and Ren, or perhaps Ryo's watch got broken in the drop into the ravine and he needs to find a watchmaker + raise funds for a repair (which may unlock a time skip function or some other gameplay implication). It would be great if YsNet could put the "free" back into F.R.E.E.
This doesn't necessarily mean you can run right to the end of the game either, as I think Ryo's "kung fu" stat should be used to ensure the player is properly leveled for the fights ahead. You can definitely *find* the more advanced martial arts masters right from the point you're let loose, but they could refuse to teach Ryo until his kung fu is higher. This shouldn't play out like the artificial blocks on progress like in the rest of the series (which should be done away with now, even if it means a shorter but crucially *tighter* Shenmue experience), as there would be other story quests and activities to engage in that will naturally bring you to within a reasonable distance of hitting the required kung fu level with a little training/side content.
To avoid annoying players by having their efforts to find a master met with a level check, you could easily funnel them towards the easier masters on first playthroughs. Refusals by the ones with higher standards would then be an optional "attention to detail" quirk that would more likely be found by players actively looking for sequence breaks. If there's an NG+ option that carries over your kung fu stat, *then* you could do the quest out of sequence for some hidden scenes and dialogue.
The process of finding the masters also opens up interesting gameplay and storyline potential by making them unique, stand-out characters or there is a particularly quirky path to meeting them (like Mr. Sun in Shenmue III). A master could have lost an arm to injury or illness but is an expert in the one-inch punch or some kind of parrying technique. One of them could have died and the quest is to track down their descendant/disciple to learn from them instead. I think it would be a cool plot twist that ties things neatly into a bow if at the end of the questline it's revealed that the old man who saved Ryo's life was the sixth master - which we would find out before Ryo heads off back to the cliff temple for the endgame/climax.
Anyway, this is just what I've come up with by following a mindset that would allow gameplay and story to drive each other. It doesn't have any consideration for manpower or budget, and I sort of envisaged this taking place in the largest *single* Shenmue environment to date where Baisha is turned into a region rather than a secluded village, but you can see where I'm going with this.
It isn't "one weird trick to make your game amazing" and there are examples of this kind of joined-up thinking throughout the Shenmue games already, but making it a driving force in production could do some real good in letting the Shenmue formula take a leap forward in scale and ambition on the next one.