Well, dang! That came up fast! With the E453, as I recall, we first found out about it through a video posted by a third party. The video just panned around the top of the keyboard while a demo tune was playing. Now, with the E463, it's already showing up on Yamaha's website! Here's a link to some specs from the U.S. Yamaha site...
https://usa.yamaha.com/products/musical_instruments/keyboards/portable_keyboards/psr-e463/specs.html#product-tabsSo, yes, there is now the sampling feature, and there is now the USB audio recording directly to a flash drive. These are interesting features. The sampling looks like it will be CD quality (16-bit stereo, 44.1 kHz), so it should sound better than the old Casio SK-1! Also, the specs imply that the accompaniment track of the 6-track multi-track sequencer can now be a DJ/Groove pattern, not just a style.
With the live control knobs, it does look like the filter, reverb/chorus, and DSP can be selected to apply to either the main keyboard or the background (which I assume means the style). But can it be applied to both simultaneously? For example, can you set the filter to modify the main and dual voices, then select it to modify the style, while still saving the parameters you set for the main and dual voices? And then, can you save it all to a registration? The ability to apply reverb, chorus, and DSP to a style or drum track sounds nice, if I understand this function correctly.
But look at what has not changed. The general number of voices, as Michael said. The 48 note polyphony. The number of registrations -- still at 8 banks of 4. The number of chorus and DSP types, though there are now 12 reverb types instead of 10. It looks like there will still only be one button to do a fill in and change from A to B or B to A parts of a style. The sequencer still has about 19000 notes, though that has never been a problem for me. The number of expansion styles also stays the same, at 10. Still 26 types of harmony. And still 150 types of arpeggio, though it appears there will be more flexibility in how they can be used.
So, what remains to be seen... Will the DSP functions be better integrated to the registrations? With the E453, the registrations can save the DSP type and knob values, but not the on/off status of the DSP feature. The only way around this (that I know of) is a "work-around" where you use the low-pass-filter DSP effect, with the effect set to allow maximum frequencies pass-through, for registrations where you don't want any noticeable DSP effect. This way, when you use the keyboard, you turn on the DSP effect, and it will work for registrations where you want it, but not produce any noticeable effect for registrations where you don't want it. Will the E463 finally save the on/off status of the DSP feature in a registration? And will the Leslie/rotary speaker effect be better?
Will the sustain pedal finally have the ability to sustain the main and split parts of the keyboard? Will the sequencer have any editing capabilities? Based on what I've seen so far, I doubt it, but we'll see!
EDIT:
I don't know how long this link will be active, but this shows a more detailed close-up of the panel (click on the small picture of the keyboard to expand it)...
https://www.kraftmusic.com/yamaha-psr-e463-portable-keyboard.html?utm_source=google&utm_medium=merchant&utm_campaign=yam-psre463&gclid=EAIaIQobChMItaqR9KX12AIVgjVpCh0CEQ0rEAYYASABEgLFB_D_BwE