Much of this stuff is because the 4x does things differently than the 3x. There were quite a number of changes to the OS. Yes some things were left off; but some of them have been put back on the 3 updates already made.
The style fills now work more similar to Yamaha, but they work very well, much smoother than before. You can still use any fill and go to any style part. In fact there are even dedicated fill buttons, if you don't want to use the autofill mode.
I feel this guy was nitpicking. Maybe he doesn't understand the new method or maybe he's found something that is important to him to work the way it used to work.
My 4x has been flawless for my needs!
BTW, Yamaha is having a large number of problems with S970 regarding buttons on the right side of the keyboard not working properly. Yamaha is repairing or replacing but only if you bug them about it.
None of these keyboards are perfect, especially in the early months after release.
_________________________
DonM