The Yakuza 6 engine is a nice upgrade. Anri Okita herself in the game just makes it so much better, among other things.
As for Yakuza 6 itself, I hope there are some minor adjustments made to the final boss.
See spoiler at ones own risk:
I believe there is a tutorial on Yakuza 6's fighting mechanics right now. In fact, click the spoilers for video: