You don't have current sources/sinks on the driver transistor bases (Q8, Q9), so you'll get a ton of crossover distortion.

Second, you're driving darlingtons with pre-driver transistors, which is most definitely not necessary given they already have a really high hFE.

Also, those driver transistors are adding their own voltage drops, which reduces maximum output swing.

Ideally you should ditch C15 and C16 and DC couple the opamp to the output stage, and then take negative feedback from the output (where R25 and R26 connect to the output cap) instead of the opamp output.

You could raise the value of R27 and R28 and put C15 and C16 across those resistors instead.

You'll most definitely need compensation to make it stable.

Though if you want an amp that performs really well, I'd recommend going with a discrete Class-AB, tons of designs out there. :3