Yu is definitely susceptible to suggestions. It was actually Ryan Payton who suggested cuts to Shenmue III's opening (and cops to a little bit of the blame for the abruptness in the finished product), our very own Peter & others who got an option to turn off the picture frame/crosshair thing in Shenmue III's first person mode, and Yu's right hand man Keiji Okayasu who pushed for the Choubu-Chan hunt.I can imagine plenty of benefits from some level of collaboration (sharing of ideas/tech) between companies even it’s not a full on co-development). After all, Ryan Payton provided input for the development of Shenmue 3 (and hopefully will again for future projects).
Hopefully, Yu Suzuki is open to advice and expertise on streamlining the development process so as to get the most from whatever budget may be assigned.
Without discarding the values of the Shenmue franchise, this needs to be a slightly more mainstream game in order to attract the additional sales required for the series to be completed.
I know Yu is considered a video game auteur and a singular creative vision, but no man is an island. Any true creative knows they need feedback anyway, not only to road test their own ideas but to be inspired by the ideas of others.
As for making Shenmue more "mainstream"... I think most of us have the same general idea of what that would mean, but I've always rejected terms like "mainstream" and "modern" in the context of Shenmue. What I would like to happen next time is a refounding of its core gameplay concepts; like a F.R.E.E 2.0. That doesn't mean the next Shenmue has to be what the original was to 1999, but rather attempt a contemporary reimagining that stays true to the spirit.
Won't bore anybody with my pitch again, but imagine if the next game was unshackled from linear quest progression and you could follow up multiple objectives at your leisure. There were flashes of this in the original games, but I'd love for them to commit and just do away with simple A to B to C to D progression.