This modified circuit will have "better" performance due to negative feedback via R2 connected directly to the output and, dc coupling the op-amp to the power-transistor stage: -
The above modifications are pretty much what most class AB audio amplifiers use.
I'd like your opinion on whether I'm on the right track with this
In my opinion, you are not really going places with your design. I mean it will work but, it will have higher distortion than mine (due to the way I've implemented negative feedback) and, if you improved the op-amp type (higher speed and slew rate) mine would be even better whereas your design wouldn't improve with a better op-amp.