I have the FX9 on pre-order... my only big issues with it is that FF 50/60p is a 5K crop and that you need the XDAC extension for raw output. I’d be fine if it still needed external recorder, but both the big back AND a recorder is a bit much. On the other hand, the internal codec will be fine for 90% of my work, and for the rest 10bit 422 ProRes via a Ninja V will be just fine.
No 6K recording is also not an issue as that’s twice the file sizes of 4K. I’m already struggling with file sizes of decent codec 4K.
The FX6 will probably be an FS5-like version of the FX9. Smaller and with crappier codecs. Will be interesting to see what kind of raw output it gets.
In one of the FX9 videos a Sony representative said the change in name from FS to FX indicated the full frame sensor. Which makes me believe that the FX6 will also be full frame. My guess is that it will be announced at NAB at the earliest (and shipping a few months after). Most likely later.
The only cameras that I know of that does FF 4K 50/60p or above are VENICE, RED, Canon C700/500II and the FF Arris. All others only do 50/60p in crop mode. Which means that if 50/60p is really important to you, you might as well get a S35 camera. Or pay the big bucks. I don’t think this will change with the A7SIII.
The reason there’s no IBIS in the FX9 is that it’s not possible to combine with the electronic ND filter at this time.