Why do you think the CLP 685 would have a be "much better speaker system" compared to the CVP-709? I am really curious about that, because as far as I follow those lines the CVP always had the best speaker system of those product lines - and my first CVP was a CVP-75 back in the 90s.
I did not personally test the CLP 685, but I would really be surprised if it would outperform the 7-speaker system on the CVP-709.
The idea of getting a CLP and a Genos is interesting (and if there were a 88keys Genos-version I might be tempted *g*), but I would conclude a CVP is more than the sum of its parts.
CVP-709 is a nice package of
- good arranger functions
- home-use okay-ish sequencer
- awesome digital piano
- very good sound system for the purpose
- fun stuff like vocoder/vocal harmony/karaoke functions
All of this in a nice piece of furniture that can be but in any living room (I would definitly NOT put a Genos there - at least my XS8 sits in another room).
Especially the small goodies like the 'light-guide / follow lights"-function (which the CVP-75 also had) make this a very interesting instrument for pros and beginners alike. My 3yrs-old cannot read sheet music, but has a blast using the follow lights function.
Only downside on the current CVP gen is the keyboard (NWX) that I'm not a fan of. The Kawai CA-98 is much better in that regard (esp. the double-escapement / key repetition is a lot closer to a concert grand than the NWX).
The new CSP-series is an interesting concept - I do like the lack of buttons look-wise, but using a touch screen as your main input surface is... <insert some disgusting words here>
Youtube demos of those instruments show, that no one "wants" this.
You buy a CVP because of its integration - not for the sole features (connect your favorite keyboard via MIDI to a computer and there you have your instrument that easily outperforms ANY hardware keys/synth/whatever) - given a decent sound system. But a CVP: switch it on, and there you have it - everything nicely integrated and easy to use.
So on my side: If NAMM 2019 brings us a CVP-809 with improved action I would be "shut up and take my money!!!".