I think the circuit design is very important ,but the layout is also very very important!!Because class AB as a audio driver ,especial large power out,load res is 4 hom or 8 hom ,the parasitic resistor very easy up to 0.5 hom even 1hom ,which will seriously
degrade the performance.
And also the stable gain is very important for low THD,if high gain ,but is vary very much as the signal amplitude ,the performance may be bad than a low gain but stable gain as the signal amplitude.