The nice thing with discrete opamps is how quickly and easily they are to prototype. With a regular stock of BJTs and standard metal film resistors one can have a field day with many permutations, they actually do give a great foundation for later extending the design to a power amplifier. With NFB the current mirror does not necessarily have to be any more complicated, a simple one will do as such I ended up removing Q6 especially when one has to wire the components in air as a rats nest😀. I did not test yet whether its unity gain stable but it should be but will check