I'm sure it must be due soon. Rumour (i.e. the noises inside my head) has it that it will feature the following.

76 note keybed from the Fantom 7 (oh go on then....with poly aftertouch).

Double the number of controls (knobs and dials) of the System 8 - each knob and slider has a small LED display below it to name the parameter (a la Yamaha , Novation)

Room onboard for 16 plugouts with all those controls automapped as currently on the S8.

Not limited to Roland synths in the plug-out range - if I could plug my 6 Cherry Audio softsynths inside the System 16 then i'd be quite happy......come on Roland if they can model those wonderful old American synths then so can you, or if not then licence the bloody things from Cherry as they're great sounding synths. Or imagine a GX80 loaded up (if you want to stick to Japanese).

Onboard performances could mix any sound from the installed plug-outs.

Onboard memory for 1024 patches (per plugout) and 512 performances (if we're still sticking to binary numbers in 2025) with usb key support for more - all user rewriteable.

MIDI 2.0 I assume.

I could go on....but that would do for now.

Lastly......£500? No......thought not.
Seriously they could probably easily shift something like this for north of £3K. It would be the greatest synthesizer ever wouldn't it? I'd be saving my pennies or maybe relying on Santa!