[ihuk]

No. 737 MAX behaves differently from 737 NG under certain conditions. MCAS makes it behave as 737 NG under those conditions. This makes it so that 737 NG pilots can fly 737 MAX without additional, and expensive, training. This is what they mean when they say MAX has the sam type rating. There is nothing inherently unstable about 737 MAX. It's not as if it does not fly without MCAS.

Problem with MCAS, as implemented on MAX, is that it has too much authority and can prevent pilots from maintaining controlled flight under certain conditions such as if feed wrong input from angle of attack sensor.

There are aircraft that are aerodynamically unstable and require flight control systems to maintain controlled flight but they are not used in civil air transport.