I don't mind them taking more time to polish the game, we've been waiting for this more than fifteen years so what's a few more months?
What "worries" me is that I think december is the best month of the year to launch the game. It's when most of the people buys games as a present for christmas. It's a shame to lose this opportunity but I don't want them to hurry the production to meet this date, difficult decision!
What I'm sure it's that Suzuki will release the game when it's done under his standards.
I dunno if launching in December is that crucial. This year has shown that games - niche Japanese games in particular - can be Million + sellers launching in February, March, April, etc. I hope Shibuya Productions/YSnet are paying attention to this trend, because it might allow for Shenmue III to launch with relatively little competition.
I wish Sega would lend more support to Shenmue III than they are right now. What gets lost in discussion is that III will not finish the series, and I really hope that Shenmue IV does not have to go through Kickstarter to get developed.
I'm concerned that Shenmue III will look like "generic ABC unreal engine" game instead of a game that looks like a Sega game. When you look at Yakuza, you can immediately tell that it's a Sega game without even knowing what it is. But from what I've read from Peter and others who have seen the game there's no need for concern.
SEGA have done enough by licencing the IP. It's very exceptional for something like that to happen, let alone a licencing deal that allows for a crowdfunding campaign. It's really only through the virtue of SEGA not giving a fuck about Shenmue, Yu Suzuki being who he is, and the remaining friends he has in the upper ranks of SEGA that this could happen.
Maybe SEGA will step up to the plate if Shenmue III is successful enough, but even then if it does well enough YSnet and Shibuya Productions may be able to produce the game without the need for any assistance outside publishing duties.
As for Unreal Engine:
Unreal Engine 3 had a common complaint of making games look similar because of a fairly inflexible shader and materials system. Unreal Engine 4 is the total opposite of that and allows for massive flexibility in how a game presents visually. There is no Unreal "look" with UE4, just developers who don't/can't invest their time and budget into customising the visuals.
Since screens and video started coming out of the game in development, we've seen that YSnet is working towards tailoring the engine to fit their vision. Chromatic Aberration was either removed or massively toned down, the colours are brighter with higher contrast, the skyboxes look vibrant and colourful, shaders have been tweaked, specular maps have been adjusted from default, etc - and they're still working towards a final visual look.
Don't get too obsessed with whether the game has an "Unreal look" or a "SEGA look", because you're always going to see the one that fits your preexisting beliefs. It's called confirmation bias.
Funny anecdote: when Yakuza 6 was revealed, the prevailing opinion on GAF was that they were using UE4. ¯\_(ツ)_/¯