All that to say, be careful with the CA78 as many have had the same issues with muted keys and it greatly altered the expression and playing enjoyment. The CS and CA98 may be better purchases due to quality control issues with the 78 it appears (it seems the issues is in the touch pad sensor on them and is not fixed by the latest updates)
Maybe I misunderstand you, but you make some dubious, and not very logical claims here.
First you say that the CA78 may have problems with muted keys (which I can't remember reading about at all) and then you say that the CS and CA98 won't have that. But they have the same action as the CA78, so why does this alleged "muted key" problem exist only with the CA78?
Then you say it's because of quality control issues, which you claim affect only the CA78, not the CA98 (where have you heard that?) and that these issues are with the touch pad sensor and haven't been fixed in the latest update. First of all, any issues with the touch pad would not result in "muted keys", so how is that even related? Second, if there are issues with the touch pad, then these issues would definitely affect also the CA98 and even your own NV10, because CA78, CA98 and NV10 have the same touch pad hardware and touch pad software.
All in all, you are raising a scare about the CA78 that doesn't seem to have any backing in facts (at least not in facts that wouldn't also affect the CS8/CS11/CA98, if we speak about the action, or the CA98/NV10, if we speak about the touch pad).
Oh, and BTW: Congrats on your NV10! Welcome to the club! Have you seen our "NV10 Hands On" mega thread?
It is dubious and logically questionable to you because you are operating on some false premises that cloud your ability to reach a valid conclusion in this case.
There are many cases of this issue with the ca78, this is one thread but I have read more. Some people tried adjisting the individual key volumes, some people talked in detail with kawai and no solution could be reached, some people tried in vain to update to the newest software, one person out of australia in detail analysed the individual velocity numbers with a separate program and found marked variation and convinced them to replace the sensors and once the touchpad sensor was replaced this fixed the problem (the only known resolution for the issue). I noticed this issue on the showroom floor, but they convinced me the update would fix it (there was an updated ca98 on the floor that did not have this issue and had a very even velocity registration and tone. The NV10 is superior to either of those in eveness of playing and expression.
The nv10 uses optical sensors tracking the position for the hammers of the millenium 3 action not the touchpad of the grandfeel2 in the CA series. I believe the optical sensors are more similar to the atx3 hybrid uprights (which are fantastic to play in digital mode).
3)the ca78 i tested (and purchased) had this problem with "muted keys" in the c2 to c4 range that dramatically affected the expression of the keyboard, even after updates. The CA98 did not. The NV10 is about as close as you can get to the feel of a real grand as you know, and was even more even and consistent (likely due to the optical sensor system). I decided I didnt want to mess with the ca78 issues or have major surgery performed on it, and decided to just go all in on the nv10.
I have found no reports of CA98 or CS muted keys and my own experience on several 98s confirmed they didnt have the issue, so my advice was to go up to a 98 or CS where the quality control might be better, or of course nv10 or atx3 are better still. But if getting a ca78 would definitely test it for muted keys before purchase at a minimum, or to be safe just avoid it all together and get one of the superior CS or CA98 instruments.
So that is the longer less stream of consciousness version of what I was trying to say.