Maybe I missing something, but looks like a software update to make MCAS more robust. And if it bug, raise an alarm and flight-crew operating procedures should be (?) to deactivate MCAS and fly without ?
Could pilots actually fly the plane without MCAS ? It must feels like an entirely different aircraft.
No, if MCAS is disabled then the vast majority of the time it will fly just like normal. MCAS is only there to adjust flying characteristics when the wing is at a high angle of attack.
No, that's a Boeing talking point. It's there to prevent the aircraft from stalling, not to 'adjust flying characteristics.' The nose pitches up during high thrust, MCAS kicks in to to counter what the pilot is doing (stick and thrust) so the plane doesn't stall.
This is entirely the problem. If MCAS operates, you're already doing something wrong. It was required in the first place because the likelihood of pilots doing something wrong is high. Now, instead of MCAS backing up the pilot's bad decision making, it might cut out at a critical moment.
We already know that Boeing revised (increased) the authority of MCAS without notifying the FAA because testing found the MCAS to be inadequate initially.
You can't simultaneously need MCAS and be okay with it being disabled intermittently. Those two things are directly at odds.
I'd be comfortable with taking it as a given this is not an avenue worth excavating.