Well, to picture it: imagine you have two cars. And one has all things needed to drive, which means a seat, a steering wheel, a gas pedal and a brake. And the other one is a car as you know it from real life: handbrakes, gearshifter, radio, lights, indicators, speedo, air conditioning, reading lights, navigation system, etc. etc. And it behaves more like a real car (flight model).
I really don’t want to blame Asobo. They’re doing a great job. The vanilla A320 is not that bad (as I described above). But they intentionally decided to have more planes on the sim, with the lack of detail, and leave the more detailed modeling to third party developers. And that’s an understandable decision.